SLI how to get the best performance

Hey Rycil, my mistake - I don't think you'll need to. I was thinking from memory when I ran multiple screens on a single card and 5760x1080 wasn't listed as an option, so it was by setting it in this .ini file that I got it working. Now that I'm using nvidia surround, 5760x1080 shows as a legitimate resolution so I needn't do it anymore. If you make changes in the front end, they will override what is written in this file. Open it with notepad and take a look, its fairly simple, but as I say - I don't think you'll need it unless you're not in 'surround' mode.

@martcerv - thanks man, your posts have been a huge help - you've done some serious investigation! Hope the devs are paying attention to your findings. I never use the dev apps, maybe I should start!

 

BTW I notice people are saying the latest nvidia drivers have an Assetto Corsa profile - does this mean in the driver, in the geforce experience thing or in nvidia inspector?

 

It's in the driver.

Right click desktop
Left click "NVidia control Panel".
Select "Manage 3D Settings" in the "3d Settings" section of the menu tree.
In the panel on the right then click the "Program Settings" tab.
In the "Select a program to customize:" box select "Assetto Corsa (acs.exe)".

 

So do we make our adjustments for the game in there to get the best results? Or are we still using the in game settings to try and fine tune?

 

ok Guys, I made some further testing tonight.

I reinstalled my second 660 and enabled sli with the latest beta drivers. Then I unticked the full screen and I didn't get stutter... BUT, the FPS was very low. Almost half of the FPS with only one GPU. And the GPUs were at 97% each...

I gave up with the drivers testing. I took off the second GPU and back to a normal situation.

I will try later when the game will be realeased and nvidia drivers stable.


Question: is there any tool to test that sli is working properly? I don't have any other game installed as I only play AC. Should I donwload 3dmark or something else?

 

the only way I know to detect SLI is really functioning is to see if both cards GPU usage goes up in relative sync. That and temp. I used nvidia inspector for that job.

It's frustrating, I had the very same issues but I think that CPU load is a killer (dunno your specs, but my i7 is a 920, which is pretty old and its clocked to 3.2 yet I still get awful fps in certain situations, like pile ups with loads of AI) and SLI isn't as good as it should be. Running 3dmark in surround mode saw poor performance too, even though it only uses a low res my results were something like 60fps versus 500fps for SLI max in one of the game benchmarks, and a single card would net me 300 odd. I'm really not sure what really did it for me, but I basically dropped all my settings bar the resolution I wanted, set nvidia inspector to default with the assetto corsa profile loaded and ran in windowed mode. Seemed to do the trick for me.

 

Thanks Martyn, I do appreciate your help. I didn't read any positive feedback from people using 660 sli, so I guess that I would be more or less alone in this situation.

As I get almost 60fps everywhere with only one 660 loaded at 98%, I tend to believe that there is something wrong with the drivers as I get less than 60fps with 660 sli loaded at 97% each.

I will try 3dmark and maybe other games or demos to check the performance of my system without and with sli.

Thanks

 

Yeah that's SLI not working properly for sure. I know this is probably obvious but you do have the surround mode enabled for a single large resolution as seen by windows, and not simply the 'display all monitors' mode, right? I still have my 3dmark results somewhere so if they're of interest for the sake of comparison let me know and I'll dig 'em out for you. As it happens I think the Heaven benchmark is better, as it'll run at high res as well as in a window, so you can find out what your best resolution is and start to work out savings from there (ie: huge res starts to take a hit, drop AA). Trouble is it can take seemingly forever, when all you really want to do is play assetto corsa, but once it is working its really nice. I'm happy with my perfomance now, and confident it will improve as Assetto starts to become more significant to nvidia and hopefully the driver improvements will follow. I agree the drivers are where the problems are. Just trying to get surround mode to actually work for me was a ball ache, it would keep switching back to display all adaptors without me even realising for a while, and I had to use cutoms resolutions, with custom refesh rates and custom polarity setting the same res for all screens (in my case it was 1920x1080@60hz with -/+ polarity, but I tried about a million other variations before realising this one worked! *sigh*)

 

Yes sure, I have surround enabled and use 3 same screens 1280x1024 each. I even use special resolution with bezels adjustment.

I am just tired of installing and uninstalling the card and the drivers instead of having fun with AC and my home made cockpit using G25 with custom wheel, frex shifter, and very old BRD speed 7 pedals which worked fine since the first day (more than 10 years, I'm afraid I'm getting old...,)

 

Seems like everything I think was a couple of years ago is actually ten years ago now. I sympathise!

Best of luck chap!

 

I have absolutely no issues with SLI in AC. I have V-Sync enabled @ 144hz on a single monitor though.
On starting grid at the lowest points my FPS hovers around 90, once the pack is spread out I never see lower than 144fps.
The only options I have turned down are smoke generation on Normal and Cube Map resolution on medium.

It took a lot of overall tweaking to get SLI the best it could be for my system, but it took zero game specific configuration.

 

Yeah, single screen seems fine with sli, it's just multi screen where things seem to go south. With single screen I can max everything, including sparse grid antialiasing on textures which looks brilliant. Would love for drivers to mature such that I can enable that in triple mode and still get good perf!

 

I just did some testing as I wanted to be able to compare builds and driver versions. Being pre release things have changed a bit each build and its good to try and understand what and why. I have had some things come up that dont make logical sense like the shadows and mirrors.

Its also good to try out the various options as there is not much point maxing everything out if the only thing that looks different is the lower framerate.

Im all for eyecandy but if the performance hit is not worth the candy I will not use it. Also being a single screen user things will vary and they always will for everyone so use some of it as a guide and best to try some things to see if you find the same results as I do.

I tried a single card and found smoke has hardly any effect on fps even at ultra where in sli its a performance killer. Visually its still hard to tell the higher settings from the lower ones so I dont mind turning that down.

Cube res seems to be less hit in the current build and nv driver too. The ac code is also imoroving each build so between now and release we should either get it to run much better as is or look much better at similar performance.

 

I cannot get SLI working properly on my set-up, iRacing - no issues, but AC = 60fps max, with massive slow down at the start of races (only 1st few seconds) drops to 30fps, was as low as 16fps until I changed cube settings / faces

 

The official statement from the devs is that sli is not yet supported until the 1.0 will be out and the nvidia drivers will support AC.

 

for those with win8.1, sli and 3d vision: save your time, its not a setting thing!
its a win8.1 bug

https://www.assettocorsa.net/forum/index.php?threads/3d-vision-sli-win8-1-bug-no-ac-bug.8814/

on win7 everything works great, especially with 337.5

 

Ok, thanks - appreciated, I will stop trying to mess about then, turning off smoke effects has given a solid 60fps even at the start, so that's better - not 200 fps I get on iRacing, but certainly better

 

Bugger..... Thanks tho

 

HI all i'm new here. I'm Running 4SLI 780HOF and at the start Game goes low on FPS then fine but i don't see it fluid...I used a recommended setting with some NFS profile but even that NVIDIA shows SLI recommended it's not a official NVIDIA profile as it's not on GeForce Experience you can see here

 

sorry forgot the Inspector screen this i used and changed to four and force AFR and its working nice