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Gained Only 10 FPS with SLI. Really?

Ho3n3r

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Oct 20, 2010
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Total SLI n00b here.

So I gained about 10 FPS with SLI as opposed to single GPU in rFactor 2 - similar story in rFactor 1. Really? Is this all you get for having 2x the GPU power in this game? I've read that with SLI you can expect only about 80-90% of the performance of a single GPU increase, but in rFactor 2 it's only about 7% for me.

Any advice? This is ****ing me off a bit to be honest.

PS: I have Force Alternate Frame Rendering enabled in NVCP. I've tried both 1 and 2, same performance as one another.
 

Ho3n3r

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Sorry but you have been here long enough to know, that rF2 has absolutely no SLI optimization. If you have bought it only for rF2, sell it (probably the best advise). You can be happy to have a 10FPS gain. A lot of people have an FPS loss with SLI.

http://www.racedepartment.com/threa...iple-screens-tips-for-good-performance.84824/
http://www.racedepartment.com/threa...st-w-practically-no-image-quality-loss.97303/
Lol. I had no idea actually. I didn't think a game would be so badly coded that SLI means nothing.

Obviously I didn't buy it only for rFactor 1/2, as they are far from the only games I play.

But still ridiculous, thought because the FPS is inherently very low, SLI would fix some of it.

And it doesn't even help one posts it on Isiforums, as Tim will come with a snotty reply like "It's not important enough so we don't have it on our agenda".
 
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Have a look around in some forums. I read somewhere, that the nvidia profile for rF2 is broken as well and with some bit changes a few people got rather good results, but it seemed to be a bit hit and miss. For some it works out and they gain and others even turn SLi off. I never bothered thinking about something like this as everything I hear about sli and crossfire is, that you run into issues at some point no matter which game. I rather spent the money on one very good card.
 

Ho3n3r

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Oct 20, 2010
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Have a look around in some forums. I read somewhere, that the nvidia profile for rF2 is broken as well and with some bit changes a few people got rather good results, but it seemed to be a bit hit and miss. For some it works out and they gain and others even turn SLi off. I never bothered thinking about something like this as everything I hear about sli and crossfire is, that you run into issues at some point no matter which game. I rather spent the money on one very good card.
What card would you recommend though, seeing as my financial limit was really 2X 670's second hand? From what I saw, unless you go 970 or 780, which is very rare here as well as ridiculously expensive compared to 2X670's, you don't get enough performance gains to justify a single card. But now it turns out it means jack for rFactor. I'll just stick to it anyway as the performance is decent enough if I don't turn up everything to high.

I also thought 2 cards would be better for Nvidia 3d than one single, but obviously not. So we learn. Pretty new to this 3d and SLI stuff.
 

Ho3n3r

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Not on that evidence. I bought 2 670's for the same price as one 960, and one 670 almost has similar performance to a 960 already. This was basically the exact reason I went the SLI route instead. If I had to go single, the performance had to be at least 1.5x that of a 670, and in the price range of two 670's. It wasn't.

Of course, that was before I knew about the problems rFactor has with SLI. But I play plenty other games, so it's fine.
 

John-Eric Saxén

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Mmm some users are actually reporting big improvement in SLI+multiview+HDR mode on isiforums with latest build, so ISI is still working on it. Although SLI will add a bit latency, I wouldn't really use it unless I have 3 screens and really bad FPS.
 

Blkout

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Aug 2, 2010
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RFactor 2 actually has negative scaling in SLI. It will actually perform worse with SLI enabled in this game compared to a single card at least as single screens go which is probably 90% of PC users
 
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Marcel Offermans

Studio 397
Aug 9, 2010
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Multiview mode is an option you can turn on if you have three screens. It is in the graphics setup of rFactor 2 (and 1).

There are basically two ways to position three screens:
  1. You can put them all in a straight line, next to each other. In this setup, you basically have a "really wide single monitor" (with a few bezels in between). The game can then render the screens as if it was one wide view, which is a bit quicker. In this setup you should turn multiview OFF.
  2. You can put them at an angle. If you do this, you need to make sure that the distance from your eyes to the center of each screen is the same. That distance determines the angle at which the side monitors need to be. The game now needs to render each screen using a different view (because they're no longer in a straight line), which is a bit slower. The upside is that you see a lot more of the world to your left and right (which is why most people use this setup). Here, you should turn multiview ON.
 

Ho3n3r

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Oct 20, 2010
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Multiview mode is an option you can turn on if you have three screens. It is in the graphics setup of rFactor 2 (and 1).

There are basically two ways to position three screens:
  1. You can put them all in a straight line, next to each other. In this setup, you basically have a "really wide single monitor" (with a few bezels in between). The game can then render the screens as if it was one wide view, which is a bit quicker. In this setup you should turn multiview OFF.
  2. You can put them at an angle. If you do this, you need to make sure that the distance from your eyes to the center of each screen is the same. That distance determines the angle at which the side monitors need to be. The game now needs to render each screen using a different view (because they're no longer in a straight line), which is a bit slower. The upside is that you see a lot more of the world to your left and right (which is why most people use this setup). Here, you should turn multiview ON.
OK thanks. I only have 1 screen, though.
 

Ho3n3r

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So I got a 970 today. Will see how good it compares then.

Thanks for everyone's input.
 

Spinelli

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Jan 22, 2014
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SLI is pretty much broken in GSC, rFactor 1, rFactor 2, etc. unless you play in 3D, then you get some very nice scaling.

- http://isiforums.net/f/showthread.php/21360-RFactor-2-Benchmark-780-Ti-1x-2x-GPU-(SLI)-1x-3x-monitors-(Surround)-2-3D-Vision
- http://www.racedepartment.com/threads/rfactor-2-benchmark-780-ti-4930k-1x-2x-gpu-sli-1x-3x-monitors-surround-2d-3d-3d-vision-2.91750/

If you pump in a lot of super intense forms of AA from the NVidia control panel / Inspector then that may be able to hide the broken SLI of the game itself because that should be helped by SLI regardless of the game itself's good/bad SLI support.

I forgot to mention one more thing...The lower the two reflection options are set in the RF2 GFX settings, the better SLI will work. Try disabling them or setting both to low and 2D SLI will work a bit better. You can clearly see proof of this in the "Reduced" graphics settings benchmark in my tests.
 

dsuspense

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Apr 10, 2013
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Single card works fine for rF2 with the nVidia 350.12 drivers.
When I use SLI and try to run rF2 it crashes back to the desktop.

Did not have this with the 344.48 and 347.88 drivers...any ideas?
 

Ho3n3r

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Oct 20, 2010
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Single card works fine for rF2 with the nVidia 350.12 drivers.
When I use SLI and try to run rF2 it crashes back to the desktop.

Did not have this with the 344.48 and 347.88 drivers...any ideas?
No idea, as I am back to single card, as stated above.
 

Ari Antero

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Mar 17, 2015
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Single card works fine for rF2 with the nVidia 350.12 drivers.
When I use SLI and try to run rF2 it crashes back to the desktop.

Did not have this with the 344.48 and 347.88 drivers...any ideas?
I had the same experience when I experimented with SLI comptibility bits, if you have done this too or changed SLI bits turn it back to default or test this one 0x42C06402
 

dsuspense

25RPM
Apr 10, 2013
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I had the same experience when I experimented with SLI comptibility bits, if you have done this too or changed SLI bits turn it back to default or test this one 0x42C06402
That did it!
Reset SLI compatability bits back to default for rF2 and it works now...