AC: Stuttering reduction

Rick Malm · Jun 8, 2014

What can a user do to reduce or eliminate stuttering even in practice runs where their are no other cars on the track?

With Lotus F1 on Monza track I sometimes get as many as 6 stutters per lap, sometimes its 0 which is great.

What is the key cause of stuttering when running AC local vs MP which involves network response time as well as AC MP implementation?

Background:

My system: CPU: Intel i7-4770K Haswell 3.5GHz (some small amount overclocking was installed from Main Performance)
Video: NVIDIA | EVGA GeForce GTX 780Ti to 3 ASUS VE278Q 27” monitors 85hz refresh

I use a SSD memory for the AC install (The SSD is my C: drive)
My cpu usage is about 26% when AC is running. Processor Affinity shows all checked (0 to 8), Priority=Normal,
window resource monitor shows the cpus are getting used and none are any where near 100%, more like 40-50% and there are graphics showing PARKED cpus.

I turned off the car interior controllable items: no wheel, no driver arms.
I set Frame Limit to match my monitor max at 85.
FRAPS shows FPS will dip to 67 in some corners.
I tried reducing smoke generation and mirror resolution, I turned blur off completely.
I have not turn off HDR yet.
I have not tried to us msconfig and kill all background processes. I typically have firefox running in the background
which is the larger memory user (then Spyhunter4, explorer, LCore, office.bin, Steam....)
I have not tried to ALT-TAB out of AC when I see stuttering to see what is running with the resource monitor.
After I ran the resource monitor and looked at the CPU tab and saw a number of PARKED cpus I downloaded and ran a disable parking utility (edits the registry). This seems to have helped. Any problem with doing this?

http://coderbag.com/Programming-C/CPU-core-parking-manager

http://www.coderbag.com/Programming-C/Disable-CPU-Core-Parking-Utility

AC settings: Fullscreen Rendering ON | Triple Screen ON (6065x1080) | Vsync - OFF | Frame Limit - 85 | Aniso x 8 | AA x 4 | FXAA x 3 | Shadows -Low | World Detail - Maximum | HDR Color Sat On @ 92%| Smoke Generation – Low||Smoke in Mirrors OFF| Motion Blur - OFF | Mirror Resolution High| CubeMaps at Low | Faces per Frame - 4

Rick Malm · Jul 4, 2014

Minor edit below in red. I sent my computer in for diagnostics at Main Performance. I had been having some
hangs, USB3 and USB2 hub issues, and off course the stuttering that other players in this forum did not seem to be seeing with close to the same setups.
The computer, X4000k, has not returned but I have a report for those that are interested.
These guys at Main Performance are VERY helpful and have always given me very fast support 24/7 support.
After they made some Nvidia control panel changes and in game changes they found no stuttering. They said the core clock running stable on the GPU, CPU an in is turbo boosting as it should, nothing out of ordinary. Memory was also stress tested with no errors, as well as CPU, PSU and GPU using a different diagnostics. No issue was found with Raid0 and as a matter of fact the President of the company (Michael) runs with Raid0 but has 2 780ti SLI on his personal game computer. Due to some events that I had recorded did replace the motherboard, and usb hub and update the bios with respect to some USB issue. Main Performance found USB ports were reporting erratic behavior when a low speed USB device was plugged in, so something was wrong with the motherboard and they replaced it.
Key Bottom line:Their staff did not agree with my AC in game setting vs Nvidia settings, and same issue with Heaven settings. They made adjustments and reran benchmarks. They saw no stuttering and got better Heaven benchmark numbers and
they said I should NOT be running bezel correction since the the ASUS 27” triple monitors do not support anything above 5760x1080. They said that trying to run a higher resolution could also have been the cause a performance issues. They wanted me to only use the in game bezel correction and the proper resolution.
They said that that saw no stuttering/jerking in Heaven except for in the sections where the FPS goes below the monitor refresh rate. I got some education: "The Heaven jerking, not stuttering, and is actually an effect of the monitor itself, not the video card. It's because the monitor is no longer displaying frames 1 after the other, and tends to skip a frame. Stuttering is where the card actually has an issue, and does not send a steady signal. Stuttering happens when one is at or above and core clock results dip with it - no such event ever occurred with your system, the core clock remains perfectly stable. We've noted no stuttering whatsoever. Jerking - you cant fix on a benchmark like this. You'll have to average over 60fps for that, as fps and hz are kind of linked. 60fps or more + 60hz = perfect smoothness. VSync would keep those numbers identical, but induce input lag and is not recommended for racing sims. On a 60hz monitor you cant technically see anything more then 60fps, but going above does not hurt."

Main Performance recommended “Nvidia Control Panel Settings” below and says that in game settings should always match. They said use these Nvidia setting at all times. They said be careful to not turn FXAA on. Since turning that off changes things to Multi-Sample AA which is typically what you want.
They said be sure to use: 16x anisotropic filtering, 4x anti aliasing and recommended no using AA8x given the performance improvement with 4x and little if any image change. Main Performance recommended that one should always forced graphic settings from the viewpoint of the driver. In game settings should always match, no matter what.
There was one outstanding issue between AC recommendation of setting AA and AF to 0 in Nvidia CP and Main Performance recommendation of setting them in Nvidia CP to AF16x and AA4x. I posted this as a question to the AC developers in another thread and one of the AC developers said that their message is obviously an error, it's just "let the application decide". I attached a screen capture of the on screen AC recommendation that people should ignore. My computer will be shipped back on 7/14. I will post the results.

Below are the Main Performance's recommended settings Nvidia Control Panel given my computer.

Ambient Occlusion: OFF,
Anisotropic Filtering: 16x,
Anti-aliasing – FXAA: OFF,
Gamma Correction: ON,
Anti-aliasing Mode: Override any app setting,
Anti-alasing setting 4x,
Anti-aliasing Transparency: OFF
CUDA - GPUs: ALL,
Maximum Pre-Rendered Frames: Use the 3D application setting
Multi-display/Mixed-GPU Acceleration: Multi display performance mode,
Power management mode: Prefer Maximum Performance
Preferred Refresh rate Highest available
Texture Filtering - Anisotropic Sample Optimization: OFF
Texture Filtering Negative LOD Bias: ALLOW
Texture filtering Quality: QUALITY
Texture filtering Trilinear Optimization: ON
Threaded Optimization: AUTO
Triple Buffering: OFF
Vertical Sync: OFF

AC's graphic setting defaults are:

Anistorpic Filtering 4x,
AntiAliasing Samples 2x,
Framerate limit Off,
Vertical Sync Off

Hope this info helps other people searching for good settings.

Blkout · Jul 4, 2014

Thanks for the info Rick but...I dont use those exact settings and I dont have stutters so its safe to say that those settings are not the magic bullet. While I agree with most of those settings, I've always used a few others with no ill effect. Cant say whether the bezel correction was causing your problem but I guess you'll know soon. Not sure if it matters though as this may be completely independent of your issue but it appears that Kunos has made several updates since you sent your PC back to Main, to address multi-display performance issues.

Martymcfly · Jul 5, 2014

Rick Malm said:
Update after 2 weeks. I sent my computer in for diagnostics at Main Performance. I had been having some
hangs, USB3 and USB2 hub issues, and off course the stuttering that other players in this forum did not seem to be seeing with close to the same setups.
The computer, X4000k, has not returned but I have a report for those that are interested.
These guys at Main Performance are VERY helpful and have always given me very fast support 24/7 support.
Their company's diagnostics did not find anything abnormal. After they made some Nvidia control panel changes and in game changes they found no stuttering. They said the core clock running stable on the GPU, CPU an in is turbo boosting as it should, nothing out of ordinary. Memory was also stress tested with no errors, as well as CPU, PSU and GPU using a different diagnostics. No issue was found with Raid0 and as a matter of fact the President of the company (Michael) runs with Raid0 but has 2 780ti SLI on his personal game computer. Due to some events that I had recorded did replace the motherboard, and usb hub and update the bios with respect to some USB issue.
Key Bottom line:Their staff did not agree with my AC in game setting vs Nvidia settings, and same issue with Heaven settings. They made adjustments and reran benchmarks. They saw no stuttering and got better Heaven benchmark numbers and
they said I should NOT be running bezel correction since the the ASUS 27” triple monitors do not support anything above 5760x1080. They said that trying to run a higher resolution could also have been the cause a performance issues. They wanted me to only use the in game bezel correction and the proper resolution.
They said that that saw no stuttering/jerking in Heaven except for in the sections where the FPS goes below the monitor refresh rate. I got some education: "The Heaven jerking, not stuttering, and is actually an effect of the monitor itself, not the video card. It's because the monitor is no longer displaying frames 1 after the other, and tends to skip a frame. Stuttering is where the card actually has an issue, and does not send a steady signal. Stuttering happens when one is at or above and core clock results dip with it - no such event ever occurred with your system, the core clock remains perfectly stable. We've noted no stuttering whatsoever. Jerking - you cant fix on a benchmark like this. You'll have to average over 60fps for that, as fps and hz are kind of linked. 60fps or more + 60hz = perfect smoothness. VSync would keep those numbers identical, but induce input lag and is not recommended for racing sims. On a 60hz monitor you cant technically see anything more then 60fps, but going above does not hurt."

Main Performance recommended “Nvidia Control Panel Settings” below and says that in game settings should always match. They said use these Nvidia setting at all times. They said be careful to not turn FXAA on. Since turning that off changes things to Multi-Sample AA which is typically what you want.
They said be sure to use: 16x anisotropic filtering, 4x anti aliasing and recommended no using AA8x given the performance improvement with 4x and little if any image change. Main Performance recommended that one should always forced graphic settings from the viewpoint of the driver. In game settings should always match, no matter what.
There was one outstanding issue between AC recommendation of setting AA and AF to 0 in Nvidia CP and Main Performance recommendation of setting them in Nvidia CP to AF16x and AA4x. I posted this as a question to the AC developers in another thread and am waiting for a response. I attached a screen capture of the on screen AC recommendation.

Below are the Main Performance's recommended settings Nvidia Control Panel given my computer.

Ambient Occlusion: OFF,

Anisotropic Filtering: 16x,

Anti-aliasing – FXAA: OFF,

Gamma Correction: ON,

Anti-aliasing Mode: Override any app setting,

Anti-alasing setting 4x,

Anti-aliasing Transparency: OFF

CUDA - GPUs: ALL,

Maximum Pre-Rendered Frames: Use the 3D application setting

Multi-display/Mixed-GPU Acceleration: Multi display performance mode,

Power management mode: Prefer Maximum Performance

Preferred Refresh rate Highest available

Texture Filtering - Anisotropic Sample Optimization: OFF

Texture Filtering Negative LOD Bias: ALLOW

Texture filtering Quality: QUALITY

Texture filtering Trilinear Optimization: ON

Threaded Optimization: AUTO

Triple Buffering: OFF

Vertical Sync: OFF

AC's graphic setting defaults are:

Anistorpic Filtering 4x,

AntiAliasing Samples 2x,

Framerate limit Off,

Vertical Sync Off

Hope this info helps other people searching for good settings.

Hi Rick
I am not sure if you remember my first advice to you. You need a bit of learning and tweaking to do do with your PC setup. I have kept quiet and not replied to any of your posts for a while as I read all the trouble shooting and all the recommendations that were made to you. Some were absurd.
Your complex and stellar PC components and setup needs time for you to understand how it can effect AC game play or any other AAA game. There is no quick one right setting that can run this game especially with your triple screen. Stop spending your hard earned IBM $$ and turn every setting down and enjoy the game. Little by little turn your settings up one by one until you notice slow downs and stuttering. With your set up I would at least start somewhere in the middle. And Rick no matter how much you play around with the settings and graphics the game will still unexpecatcly stutter. This is what cutting edge graphics, physics and MP games just do. You need time to tame that system and be happy with it.

Blkout · Jul 5, 2014

Martymcfly said:
Hi Rick
I am not sure if you remember my first advice to you. You need a bit of learning and tweaking to do do with your PC setup. I have kept quiet and not replied to any of your posts for a while as I read all the trouble shooting and all the recommendations that were made to you. Some were absurd.
Your complex and stellar PC components and setup needs time for you to understand how it can effect AC game play or any other AAA game. There is no quick one right setting that can run this game especially with your triple screen. Stop spending your hard earned IBM $$ and turn every setting down and enjoy the game. Little by little turn your settings up one by one until you notice slow downs and stuttering. With your set up I would at least start somewhere in the middle. And Rick no matter how much you play around with the settings and graphics the game will still unexpecatcly stutter. This is what cutting edge graphics, physics and MP games just do. You need time to tame that system and be happy with it.

No offense to you, but most of the suggestions that were made to him were all good suggestions and part of a good troubleshooting methodology, That being said, if you think his problem is nothing more than turning graphics settings down, maybe you should spend a bit more time reading this whole thread. I find it hilarious that you come along now and pretend that you knew the solution all along but just have just now showed up to help him. I'll save you a little time and just tell you that he's already tried turning down all the graphics details in AC and he even tried running the game on a single monitor at 1080p resolution which his 780ti graphics card should have been able to run exceptionally well at that resolution, yet he still had stutters. This wasn't a case of occasional stutters, he was getting multiple stutters in 3- 5 laps of every race. That is not normal for his hardware, I don't get any stutters and my hardware is very close to his.

Martymcfly · Jul 5, 2014

Blkout said:
No offense to you, but most of the suggestions that were made to him were all good suggestions and part of a good troubleshooting methodology, That being said, if you think his problem is nothing more than turning graphics settings down, maybe you should spend a bit more time reading this whole thread. I find it hilarious that you come along now and pretend that you knew the solution all along but just have just now showed up to help him. I'll save you a little time and just tell you that he's already tried turning down all the graphics details in AC and he even tried running the game on a single monitor at 1080p resolution which his 780ti graphics card should have been able to run exceptionally well at that resolution, yet he still had stutters. This wasn't a case of occasional stutters, he was getting multiple stutters in 3- 5 laps of every race. That is not normal for his hardware, I don't get any stutters and my hardware is very close to his.

No offense taken Mike.
The bottom line is that I am only replying to Ricks very long Post. Obviously he is putting in a serious effort and resources in getting AC to work smoothly as possible. And yes I have been following this thread very closely and read every post since the beginning. But once I started reading in his last Post that there are some guys from Tiger Direct running benchmarks and telling him how to run Assetto Corsa I have to step in. Rick is getting the wrong advice.
Mike, from one PC builder to another. I think you understand that Rick got his PC built for him by someone else. You understand that his PC set up is not the same us going to Best Buy and buying PS4 and playing Gran Turismo. There is a learning curve that he needs to comprehend before he starts tweaking Assetto Corsa.

Rick to be honest with you, after I told you to download Afterburner I realized that you need to go out there and learn how to drive all that incredible machinery yourself instead of sending you on a wild goose chase. Then you will understand how to run Assetto Corsa to your liking.
Mike please don't argue with me anymore if anything lets have a race online and take it to the track buddy...

Blkout · Jul 5, 2014

Martymcfly said:
No offense taken Mike.
The bottom line is that I am only replying to Ricks very long Post. Obviously he is putting in a serious effort and resources in getting AC to work smoothly as possible. And yes I have been following this thread very closely and read every post since the beginning. But once I started reading in his last Post that there are some guys from Tiger Direct running benchmarks and telling him how to run Assetto Corsa I have to step in. Rick is getting the wrong advice.
Mike, from one PC builder to another. I think you understand that Rick got his PC built for him by someone else. You understand that his PC set up is not the same us going to Best Buy and buying PS4 and playing Gran Turismo. There is a learning curve that he needs to comprehend before he starts tweaking Assetto Corsa.

Rick to be honest with you, after I told you to download Afterburner I realized that you need to go out there and learn how to drive all that incredible machinery yourself instead of sending you on a wild goose chase. Then you will understand how to run Assetto Corsa to your liking.
Mike please don't argue with me anymore if anything lets have a race online and take it to the track buddy...

Fair enough, but even though Rick bought his PC from a builder instead of building it himself, I've already seen that Rick is very capable of understanding and troubleshooting his PC. He listened and tried every suggestion that was given to him and there were literally dozens and yet he never gave up and he documented most every change with screenshots to back it up. I was honestly very impressed with Rick's tenacity and willingness to get to the bottom of his issue but in the end, nothing seemed to cure his problems so he felt he had no choice but to send it back to the builder since it was under warranty and I can't blame him in that case. I, as well as others spent a lot of time typing suggestions and trying to explain his results so I was a little offended with your statement that people were suggesting absurd recommendations and that in the end all he had to do was lower his graphics detail. I realize you probably didn't read the whole thread because that information was already in there. I apologize if I came across too strong, it just ruffled my feathers a bit. Rick has probably already learned quite a bit about his PC since he embarked on this journey to resolve this problems so I feel he deserves credit for that too. Most people that buy a pre-configured PC are afraid and unwilling to do anything to it, but Rick wasn't.

Ultimately I'm just hopeful that when he gets his PC back, it works as intended and he's able to enjoy AC.

Stelios · Jul 5, 2014

@Rick Malm , with all due respect, i think those guys are talking out of their asses.

Some **** you just transferred to us just cant be true.
I dont have much time for a full reply but i will get to it when i get back , most notably:

"they said I should NOT be running bezel correction since the the ASUS 27” triple monitors do not support anything above 5760x1080"

and :
"The Heaven jerking, not stuttering, and is actually an effect of the monitor itself, not the video card. " , how come i could see your stuttering in the video you uploaded.

Back later...

Martymcfly · Jul 6, 2014

Blkout said:
Fair enough, but even though Rick bought his PC from a builder instead of building it himself, I've already seen that Rick is very capable of understanding and troubleshooting his PC. He listened and tried every suggestion that was given to him and there were literally dozens and yet he never gave up and he documented most every change with screenshots to back it up. I was honestly very impressed with Rick's tenacity and willingness to get to the bottom of his issue but in the end, nothing seemed to cure his problems so he felt he had no choice but to send it back to the builder since it was under warranty and I can't blame him in that case. I, as well as others spent a lot of time typing suggestions and trying to explain his results so I was a little offended with your statement that people were suggesting absurd recommendations and that in the end all he had to do was lower his graphics detail. I realize you probably didn't read the whole thread because that information was already in there. I apologize if I came across too strong, it just ruffled my feathers a bit. Rick has probably already learned quite a bit about his PC since he embarked on this journey to resolve this problems so I feel he deserves credit for that too. Most people that buy a pre-configured PC are afraid and unwilling to do anything to it, but Rick wasn't.

Ultimately I'm just hopeful that when he gets his PC back, it works as intended and he's able to enjoy AC.

What really got my attention to this thread in the first place is that I have the same problems as Rick Does. My Assetto Corsa gaming experience stutters during Single player races, Multi player races and other various scenarios. This game stretches my PC to its limits for what ever reasons. You have sent numerous posts claiming that your gaming experience is perfect without any game stutters. I congratulate you on achieving that sweet spot as I can't do it with my better then average system.

I finally settled with the occasional stuttering and just started to enjoy the game as it progresses with each update. I had the same high expectations thinking that my Beefy PC will run this game silky smooth, but it doesn't. It's not because of my SSD hard drive, Ram, CPU or what ever. The game stutters and that is why Rick needs to hear it from players like myself that experience the same issues as he does. One of the mistakes that myself and other new members to join the PC community that dished out over 2K$$ on a PC is that my PC will run everything smoothly. It doesn't work that way.

Jason Hunt · Jul 6, 2014

Yes, but it's not always as simple as that.

Mine runs very well but I had a series of stutters which was down the the AI pitting on certain tracks. It was actually unplayable at one time because there was a an additional bug causing them to run out of fuel so they all started pitting together.

That's gone away now and my game mostly runs very well but I've not changed anything at my end.

There could be other issues like this that some people are experiencing now that we haven't. And we have to try and diagnose them. I diagnosed mine by sitting at the exit of the pit lane, looking in reverse view, and watching the resource meter peak when the AI pitted.

Therefore, this useless advice as you see it serves a purpose because the solution might not be just to turn settings down - which wouldn't have made the slightest bit of difference in my case.

The other big question is to clarify what 'stutter' actually means because different people will explain things differently.

Blkout · Jul 6, 2014

Rick's stutters were probably obvious to him since he was actually monitoring frametime. You can have good framerate but have frametime spikes which will cause a momentary microstutter. As a general rule the higher the framerate, the less chance of frametime spikes but even at 60fps, its possible to get frametime spikes as Rick has shown. With a single video card, he should have very low frametime, at least less than 16ms. When you run more than one video card, frametime increases due to the fact that both cars have to be synchcronized to get a smooth image. When I checked my frametimes for AC using two 780's in SLI, I was right at 16-17ms and it never wavered which gave me very smooth gameplay. I believe Rick's frametime spikes were well above that and happening a few times per race which is very unusual for a single video card. Here's a couple of articles I dug up on frametime vs framerate. There's dozens on the internet though if you wish to read more about it.

http://www.mvps.org/directx/articles/fps_versus_frame_time.htm

http://www.vortez.net/articles_pages/frame_time_analysis,1.html

Michael Main · Jul 12, 2014

Hi Guys,

Thanks for the link Rick - hopefully I can provide a bit of helpful info here.

We believe the issue with Rick's problems were associated with a lot of mismatched graphic settings, and what seemed to possibly be a USB issue on a group of USB ports on his old MB. Initial tests showed no issue with his board, but day before yesterday I tested the board with a new USB Analyzer we just got and noticed some issues with low signal USB devices causing some erratic behavior. New MB shows no such issues though, and we also added at Rick's request a 2nd GTX 780Ti.

So far to match Rick's tests with others in Heaven, the attached results show scores comparable to the highest rated scores in worldwide tests. Ricks system is benching with the top 30 or so. I have never really cared for these kinds of benchmarks though, as the scores really dont mean much. But in the world of PC benchmarking they are like the holy grail so dont shoot me for not caring haha

The MIn FPS number of 9.3 - It's not entirely uncommon though from my research to have a slight dip like that in benches with Heaven at these settings though. but will look into it a bit further.

Afterburner and other programs we use to check for stuttering show nothing either. It's my opinion that AC should run/be matched with NV's CP settings at all times, just like many other games out there.

Here is the same test at 8xAA - still very good results.

We expect to ship back to Rick on Monday - letting the system bench over the weekend with some Linpack testing and then switching over to VC stress testing with some of our diagnostic tools. I think Rick will be very pleased when he gets it back.

Blkout · Jul 12, 2014

Michael Main said:
Hi Guys,

Thanks for the link Rick - hopefully I can provide a bit of helpful info here.

We believe the issue with Rick's problems were associated with a lot of mismatched graphic settings, and what seemed to possibly be a USB issue on a group of USB ports on his old MB. Initial tests showed no issue with his board, but day before yesterday I tested the board with a new USB Analyzer we just got and noticed some issues with low signal USB devices causing some erratic behavior. New MB shows no such issues though, and we also added at Rick's request a 2nd GTX 780Ti.

So far to match Rick's tests with others in Heaven, the attached results show scores comparable to the highest rated scores in worldwide tests. Ricks system is benching with the top 30 or so. I have never really cared for these kinds of benchmarks though, as the scores really dont mean much. But in the world of PC benchmarking they are like the holy grail so dont shoot me for not caring haha

The MIn FPS number of 9.3 - It's not entirely uncommon though from my research to have a slight dip like that in benches with Heaven at these settings though. but will look into it a bit further.

Afterburner and other programs we use to check for stuttering show nothing either. It's my opinion that AC should run/be matched with NV's CP settings at all times, just like many other games out there.

Here is the same test at 8xAA - still very good results.

We expect to ship back to Rick on Monday - letting the system bench over the weekend with some Linpack testing and then switching over to VC stress testing with some of our diagnostic tools. I think Rick will be very pleased when he gets it back.

Michael, thanks for showing up. Always good to have that personal touch from a builder. I don't think anyone here ever thought you were trying to pull a fast one on Rick or that you didn't know your business so I just wanted to say that I hope you had time to review this thread and what all had been tried in attempt to resolve this issue.

I agree with you on benchmarks. I'm not a bench queen but in the world of PC enthusiasts, many can't live without them. I simply posted a freebie for Rick to try to see if anything looked unusual in comparison to my own PC and anyone else that wanted to try. My PC specs aren't all that far from Rick's so I figured if it were close, I would know from a CPU and GPU standpoint that he was ok.

I agree that Rick's PC looked fine, but something just didn't make sense with his frametime (not framerate) spikes which seem to be causing some stuttering in Assetto Corsa. What was puzzling was that he tried nearly everything with no notable solution to his problem. I went as far as I could go without seeing it with my own eyes. I have a long PC building background myself, but only for myself, family, friends and co-workers and I've done my fair share of troubleshooting. Sometimes, there's just no substitute from having the PC in front of you and diagnosing a problem in real time yourself. Its much harder to do it remotely through someone else. No fault of Rick though because he went over and beyond documenting changes.

In the end, I just hope Rick can enjoy Assetto Corsa now, certainly the additional 780ti is going have a huge effect on framerates in a triple monitor setup.

Thanks again Michael for stopping by to explain and shed some light on this situation, very respectable.

Rick Malm · Jul 23, 2014

I got my computer back and I am up again. Its been upgraded to a Z97 motherboard and I now have 2 780ti Superclock cards in SLI. Finally I can enjoy racing and not have a BIG jerk cause me to crash. I am running with very high settings in game but never change AF away from 16x and AA =4x.

Heaven benchmarked with max settings and 1 monitor at 3500. With tripl I got a scores of 1100-1200. Heaven on a triple is demanding and its not perfect but much better. AC runs smooth with the Nvidia and in game settings that I posted earlier. I did get a few small jerks 2 out of 8 races of 5 laps with 10 AI cars. Might be an AC issue. The jerks are always towards the end of the race (last turn). Last 3 or 4 races were perfect. Before the upgrade, when running SimVibe and 10 AI cars, I used to get as many as 20 big jerks in 5 laps. Now: No stutters and often no Jerks!!! One can look at the GPU clocks and if you dont see any large dips then there are no stutters that you might have missed seeing. Mike (Blkout) suggested tracking frametimes so I have captured that and did RANK style plots for Heaven and AC and attached 2 plots FYI.
I still have some tearing with both AC and GSCE and have been messing with frame rate limits of 85, 60, 59 instead of NONE but have not tried VSYNC on yet.
You have to look for it so I just dont look at the light poles or edges of signs or fence posts
and look where I should be looking (at the cars and, turn in, next apex, or exit point).

Ghoults · Jul 23, 2014

Tearing is about fps and screen refresh rate. Tears happen when the fps is a 1x, 1,2x, 1,25x, 1,33x, 1,5x multiplier of your screen refresh rate. If you really want to get the worst kind of tearing possible for 60Hz screen you run your fps at 60, 72, 80 or 90. If you run at these precise fps you see a tear (or more than one) in the screen somewhere that is either stationary or slowly goes up or down.

If you don't want tears but want fps cap you want to use fps cap that is not a precise multiply of your screen's refresh rate.

What is this precise multiply? Well let's imagine you are building a brick wall. The wall is 60 centimetres long. You have bricks that are 90 centimetres long. So you cut those 90 cm long pieces to 60 cm long and 30 cm long pieces. Then you start building your wall. As you build your wall you see that on every other row there is the a disconnection in the middle where you have put two 30 cm long bricks. Because 30 cm is exactly half of 60 cm you get the seam on the same place every single time.

If you had ordered say 77 or 83 cm long bricks and cut them to 60 + the other piece the seam would never be in the same position. For building that would look bad but for sim racing that is exactly what we want.

The thing is unless you are running vsync you always get screen tear. Always. But screen tears are only visible to human eye when they appear in the same place constantly. This is why using non-precise multiplies is important. With non-precise multiplies the screen tear appears almost randomly on the screen up or down or middle or where ever and because the tear only stays there 1/60th of a second it happens too fast for the human eye to spot it. (This doesn't mean going way above 60 fps on 60hz screen us useless though).

So if you want the most horrible screen tearing either use the exact same fps as is the refresh rate of your screen or one of the precise multiplies of those I mentioned earlier. If you don't want screen tearing you want to use multipliers that move the tear to different place on each screen refresh. 83 is a good number for 60 and 120hz displays.

Rick Malm · Jul 23, 2014

Thanks, I will try some of you numbers.

Blkout · Jul 23, 2014

Unfortunately Rick, if you haven't been following the latest AC update thread, SLI is now broken. What great fortune as you just got a second video card, right? Something in last Friday's update broke SLI and actually causes negative scaling like rFactor 2 where you actually lose performance with both cards enabled in SLI. However, there is a work-around for now which is to raise the reflection faces per frame to 6 in the graphics menu which seems to enable SLI again, however because 6 faces per frame is very graphic intensive, it does cause some performance loss too compared to lower settings. If you're a single screen user which I know you aren't, you're better off disabling SLI and using a lower setting for faces per frame until its fixed again. If you're a multi screen user like yourself, you're betting off changing faces per frame to 6 and leaving SLI enabled. What I have noticed is that with faces per frame set to 6, SLI is enabled again and your maximum framerates will go up, however your minimum framerates will go down some because 6 faces per frame is pretty tough to run.

For what its worth, I recommend running V-sync on almost all racing games except iRacing no matter what because that game has a lot of lag at 60fps with V-sync enabled. The other is rFactor 2, if you can't maintain close to 60fps, then it can get really choppy and stutter if it drops below 40-45fps. Most other games run just fine with V-sync enabled and eliminates tearing which is a big pet peeve of mine.

Rick Malm · Jul 23, 2014

Mike, Yes I did see you comments in another thread. But what are the symptoms your fail?
Mine image looks much better than before. Almost perfect.
I wish I would have captured some details of the GPU clock speed and frametimes
a month ago. My AC fps average just now is 82-89 with peak to 180-200 and minimums about 50 with a few point 30fps. No jerks. I tried 6 faces and it was not nearly as good looking given the fps drop by almost 2x. I dont know what you mean b negative scaling.