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AC in 4k@60hz - Problem

Craig Turner

100RPM
Sep 28, 2010
145
5
I am pulling my hair out here why my system won't run AC in 4k smoothly?

Spec:
  1. Win 10 Pro 64 bit
  2. I7 3960x @ 3.3GHZ
  3. RAM – 16GB DDR3 @ 666 MHZ
  4. NVIDIA Geforce GTX 1070 4095 MB (Edit: It is actually 16gb)
  5. Samsung 850 EVO SSD – 1TB
  6. Monitor - 40" JVC 4K Ultra HD TV
No matter how low the settings, it seems to run 'choppy' but still shows as 60FPS, and this is just in singlepayer ?
Is there something that may be causing this, as I am sure my specs should be able to manage it shouldn't they?
I can run everything at max in 2k with no issues, soon as I select 3840 x 2160 it turns choppy.

Any advice on this is most appreciated as I have spent most of the weekend trying to sort this out.
 
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Stereo

3000RPM
Dec 22, 2009
3,686
4,446
From what I recall AC runs physics at 3ms per physics update so you need 55.6 or 66.7Hz to make it smooth in a certain sense (equal distance traveled per frame). Not sure if that's the issue though.
 

Gero Mulkau

50RPM
Premium
May 23, 2017
71
54
34
with this low CPU Speed i would say, that you get 99% CPU warning when you drive against ai and so it looks like in slow motion
 

Craig Turner

100RPM
Sep 28, 2010
145
5
UserBenchmarks: Game 94%, Desk 80%, Work 66%
CPU: Intel Core i7-3960X - 85.4%
GPU: Nvidia GTX 1070 - 100.3%
SSD: Samsung 850 Evo 1TB - 84.2%
SSD: Intel 330 Series 180GB - 55.8%
HDD: WD Black 2TB (2010) - 44.3%
USB: USB Flash DISK 16GB - 6.3%
USB: Seagate Desktop 2TB - 11.2%
RAM: Kingston HyperX DDR3 1866 C9 4x4GB - 87%
MBD: Asus RAMPAGE IV EXTREME
 

neilparky

10RPM
Jul 2, 2017
22
2
Frametime issue?

Try capping your framerate.
Although video covers freesync/gsync , the same applies to fixed refresh.

Good explanation here,
 

Case_

6000RPM
Premium
Jun 30, 2011
6,357
6,386
44
I am pulling my hair out here why my system won't run AC in 4k smoothly?

Spec:
  1. Win 10 Pro 64 bit
  2. I7 3960x @ 3.3GHZ
  3. RAM – 16GB DDR3 @ 666 MHZ
  4. NVIDIA Geforce GTX 1070 4095 MB
Your system is not exactly suited for 4k gaming. In particular, since you say you're still getting 60 fps, I would guess you are running out of VRAM (4GB might not be enough even for a 1080p gaming, much less for 4K), which usually results in microstutters. Especially on an old system with a slow-ish DDR3 RAM.
 

Andrew_WOT

4000RPM
May 11, 2014
4,198
2,049
Turn VSync off in game and set it to Adaptive in Nvidia driver, also set max prerendered frames to 1.
You should be able to run it just fine on that spec.
And one more, try to remove all custom apps (uninstall) and remove any Kunos app from the HUD.
 

RasmusP

6000RPM
Premium
Oct 7, 2016
6,195
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Your system is not exactly suited for 4k gaming. In particular, since you say you're still getting 60 fps, I would guess you are running out of VRAM (4GB might not be enough even for a 1080p gaming, much less for 4K), which usually results in microstutters. Especially on an old system with a slow-ish DDR3 RAM.
As far as I know there is no gtx 1070 with only 4gb of vram. I searched for it quickly and couldn't find anything that would prove me wrong...
So while you're absolutely right about 4gb not being suited for 4k, that's probably not the reason for the problems here. It's more likely that whatever OP used for reading out his specs got it incorrectly... :cautious:
If you can find a 4gb 1070 you're definitely right about it probably being the cause though!
 

Andrew_WOT

4000RPM
May 11, 2014
4,198
2,049
Found my old benchmark with GTX 980 non Ti (4Gb VRAM)
https://www.assettocorsa.net/forum/...lts-food-for-thought.28103/page-3#post-572808
4K GTX 980 Classified (stock clock):
AC VERSION: 1.3.4 (x64)
POINTS: 10105
FPS: AVG=68 MIN=55 MAX=77 VARIANCE=0 CPU=30%

LOADING TIME: 13s
GPU: NVIDIA GeForce GTX 980 (3840x2160)
OS-Version: 6.2.9200 () 0x300-0x1
CPU CORES: 12
FULLSCREEN: ON
AA:4X AF:16X SHDW:2048 BLUR:0
WORLD DETAIL: 5 SMOKE:2
PP: QLT:5 HDR:1 FXAA:0 GLR:5 DOF:5 RAYS:1 HEAT:1

Game stable (mild) OC:
AC VERSION: 1.3.4 (x64)
POINTS: 11156
FPS: AVG=76 MIN=3 MAX=111 VARIANCE=0 CPU=33%

LOADING TIME: 12s
GPU: NVIDIA GeForce GTX 980 (3840x2160)
OS-Version: 6.2.9200 () 0x300-0x1
CPU CORES: 12
FULLSCREEN: ON
AA:4X AF:16X SHDW:2048 BLUR:0
WORLD DETAIL: 5 SMOKE:2
PP: QLT:5 HDR:1 FXAA:0 GLR:5 DOF:5 RAYS:1 HEAT:1
 

RasmusP

6000RPM
Premium
Oct 7, 2016
6,195
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Just to check for the vram:
I activated dsr on my 3440x1440 Monitor to run a quick race session in 4587x1920. Which 6% more pixels than 3840x2160.
MSI Afterburner reports around 5600 MB Vram used!

Here are my settings:
4k_VRAM_Test_Settings.JPG


And the session settings:
4k_VRAM_Test_Session.JPG


I also tested the same session with everything set to low, nothing off, but same resolution:
4k_VRAM_Test_LOW_Settings.JPG


VRAM 4800 MB!

So if you really happen to have a 4GB GTX 1070 then there's the problem :)

BTW, you're not somehow running AC in 32 bit mode? :cautious:
 

Andrew_WOT

4000RPM
May 11, 2014
4,198
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Academic, irrelevant to the topic discussion but as you could see from my benchmarks 4gb is not a problem. I can still run AC and Wreckfest on that card in full 4k glory at 60fps.
FH4 requires 70% rendering scale as memory indeed becomes an issue.
Hardly any modern title gets away without swapping VRAM to page file, even on 11gb 1080Ti, it's normal and should not cause any problems.
 
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RasmusP

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Academic, irrelevant to the topic discussion but as you could see from my benchmarks 4gb is not a problem. I can still run AC and Wreckfest on that card in full 4k glory at 60fps.
FH4 requires 70% rendering scale as memory indeed becomes an issue.
Hardly any modern title gets away without swapping VRAM to page file, even on 11gb 1080Ti, it's normal and should not cause any problems.
Only time I experienced running out of vram was at friend's with his gtx 670. Don't remember the game but the GPU load was fine and with textures set to a lower setting the fps were fine too. The moment you raised the texture setting above a certain level it was a stuttering mess, without the GPU load going up.
It makes sense what you say, and I'd say you're right as otherwise there would be quite a few problems with lots of games I guess.
I'm just wondering...
 

Case_

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Jun 30, 2011
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Since I had the 970 until recently, I was struggling with VRAM constantly (it has 4 GB of VRAM, but only 3.5 is "fast" VRAM, the remanining 500MB is slower, but still faster than the system memory, especially when talking about DDR3, which I was also running until quite recently - and I would certainly hope the 666 MHz is meant to say 1600, because otherwise that's another big problem right there). Just going over the 3.5 limit meant a noticeable increase in various microstutters and lags, even if the framerate perhaps wasn't directly affected and seemed high enough. Setting the game so that it would need more than 4 GB would make things much worse in this regard. It wildly depended on the game, though - some games you would hardly notice it, some were heavily affected.

Sims tend to be affected quite a lot by this in my experience, and they're also easy to run out of VRAM due to the various high resolution liveries and all that (especially if you add custom liveries into the mix), and possibly also because, let's face it, they're not always perfectly optimized. RFactor 2 in particular is very VRAM hungry in my experience, but (as everything regarding performance in that game) it tends to vary greatly from one car/track combo to another. You can be running with barely 2GB of VRAM on one track with one car class, then load something like say the official Sebring with the two official GT3 packs, and suddenly you're at 4GB or more and you're really struggling to find settings to lower the VRAM usage below the 3.5 GB to keep the game from getting annoying microstutters (while still running seemingly fine framerates) without reducing the game to a blurry mess (and even that sometimes didn't really help).

This is one of the things racing sims once again tend to differ a lot from regular games (and one reason I wish they would be benchmarked a lot more in the media), as in regular games it seems a lot easier to not need as much VRAM and/or get away with them sometimes using the system RAM as a crutch to swap out some textures (I would certainly hope they're not using page file for that...just saying).

So yeah, that's why I immediately suggested VRAM when I saw stuttering issues mentioned with 4GB and 4k and supposedly OK framerates. It wasn't some random hypothetic suggestion on my part, it was experience. It was in fact also the primary reason why I upgraded my GPU - not because I was struggling with performance so much, but because I was regularly running out of VRAM in the worst moments possible and was getting annoying microstutters as a result. And the last thing you want in a sim during a race is random microstutters.
 
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RasmusP

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Nice Post!
About the 666 MHz: many tools read out the single frequently. One of the D's stands for double as you know :p
So he's running 1333 MHz memory :)
 
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