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SLI with 2.5 Caucasus


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Lets hope Vulkan revives the multiple cards era in a good fashion, like "old" 1080Ti plus a new 2080Ti.

 

So that buying a new card ADDS to the performance instead of replacing and making obsolete in many cases.

 

Let's hope Gen-Z makes it and replaces PCIe and board layout. It was so cool if you could add a CPU via a slot-in card, a GPU or 2 or 3, or rather one more heavy I/O card amd a 3rd CPU with more cores.

 

I am only running 1 card as SLI sucked so hard. If mGPU makes sense, I am runnimng more than 1 again.

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Ladies and gentlemen, After trying for hours and hours yesterday to get sli to work, different sli bits and settings and bla bla.... I have finally come to the conclusion and Sli DOES NOT work with DCS 2.5. In sli The fps remains the same and the usage of both GPU decreases.

 

The cards do run cooler allowing for a better overclock potential, but there are stutters which ruins the experience.

 

I have two 1070s and according to the benchmarks, in games that support sli they can outperform a 1080 ti. But not in DCS 2.5.

 

Hence 1080ti is the way to go if you want to enjoy DCS on maximum settings.

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I did the same in almost all ways possible and I agree, SLI does not really improve a lot but for me, there's no stutters at all when I use 2 cards. I think it's a bit better with 2 cards.

 

Take a look to this NVI settings but adjust AA to meet your actuals settings, just to see if there is an improvement

DCS_Test_SLI.zip


Edited by paradox64

 

Asus Rampage V Edition 10 / i9-9900k @5Ghz / 32Gb DDR4 @3200Mhz / Samsung 960 Pro M.2 / RTX2080ti / Vive Pro / ROG 3440x1440

 

You maybe saw I often edit my post. I want to tell you it's to correct spelling cause I only speak english a little and sometimes it's quite unclear... so forgive me !

 

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I have finally come to the conclusion and Sli DOES NOT work with DCS 2.5. In sli The fps remains the same and the usage of both GPU decreases.

 

Drag80, you are probably getting bottlenecked by CPU. After I initiated this thread and did a lot of experimentation, I discovered that's what happened to me. Under certain test conditions, the CPU was limiting the framerate. Because the videocards weren't the bottleneck, one gpu was able to handle the load (and two gpu's was overkill resulting in reduced gpu utilization but no increase in fps).

 

I reduced visible range and overclocked my cpu which made a massive difference. (now without a cpu bottleneck the difference between running SLI vs. single gpu was huge - went from about 44fps to 75fps, now my gpu's are probably the bottleneck again)

 

edit: I changed my first post to discuss my conclusion about SLI working or not


Edited by prccowboy
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Drag80, you are probably getting bottlenecked by CPU. After I initiated this thread and did a lot of experimentation, I discovered that's what happened to me. Under certain test conditions, the CPU was limiting the framerate. Because the videocards weren't the bottleneck, one gpu was able to handle the load (and two gpu's was overkill resulting in reduced gpu utilization but no increase in fps).

 

I reduced visible range and overclocked my cpu which made a massive difference. (now without a cpu bottleneck the difference between running SLI vs. single gpu was huge - went from about 44fps to 75fps, now my gpu's are probably the bottleneck again)

 

edit: I changed my first post to discuss my conclusion about SLI working or not

 

Check out this thread

 

https://forums.eagle.ru/showthread.php?t=203070&page=4

 

where people are talking about an application via which you can control how many cores DCS uses. Do u think We should give it a try ? its process lassoo or something

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Do u think We should give it a try ? its process lassoo or something

 

If you try processlasso(?), report your results back here. I'm curious if it has much improvement over setting w10 game mode and using high power profile

 

also, have you tried reducing your "visible range"?

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If you try processlasso(?), report your results back here. I'm curious if it has much improvement over setting w10 game mode and using high power profile

 

also, have you tried reducing your "visible range"?

 

Nop. Visibility range is set to ultra ....by the way any idea whats the difference between preload radius and visibility range. What effects do they really have on the simulation ?

 

I will give process lassoo a try. If DCS is using one core then CPU bottlenecking is quite possible. But total usage never goes beyond 20%

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Visibility range is set to ultra ....by the way any idea whats the difference between preload radius and visibility range.

 

There are other threads that explain it better but I think in a nutshell:

 

preload radius affects how much is "preloaded" into RAM vs. HDD access (so if you have the RAM you can safely max out the setting)

 

visibility range is how far out you can see objects, shadows, etc. - so this setting can have a huge impact on the cpu load in densely populated areas of the map. I would suggest lowering this setting first to see how much it frees up your cpu


Edited by prccowboy
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I want to share my experience with SLI as it has been working perfectly for me. Here is the specs of my system:

CPU:7700K (4.9Ghz fixed clock)

RAM: 32GB Corsair Dominator Platinum DDR4 (4X8GB, 3200Mhz)

GPU: A pair of Titan XP 12GB

MB: ASUS Maximus VIII Extreme

Display: Asus PA329Q (4K)

 

 

Here is my game settings:

Screen_180224_204644.thumb.jpg.fe8ab1ab58ecde8e4ecbfe46dd9a39fb.jpg

 

I tested SLI with one of the missions included in "The enemy within" campaign (3rd mission "Patrol", starting at Kobuleti) of DCS 2.5

 

First of all, with SLI turned off

FPS: 35~40 while GPU usage stays above 90% all the time

Screen_180224_201501.thumb.jpg.ee7ab480156cf8db327622e3c587519c.jpg

 

When SLI is enabled, (used default Black Shark Nvidia profile and only SLI compatibility setting DX10+DX11 bits was changed to 0x081000F5 (Dirt 3, Dirt Rally)).

FPS: 60 (V-sync on)

GPU usage of both cards hovering btw 70~80%

Screen_180224_204400.thumb.jpg.6442d664835142670bad88a602125048.jpg


Edited by babypapa1
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I want to share my experience with SLI as it has been working perfectly for me. Here is the specs of my system:

CPU:7700K (4.9Ghz fixed clock)

 

I suspect with your system that you are rarely getting cpu bottlenecked which allows your SLI to be better utilized. I have great SLI results in NTTR map but parts of the Caucasus map seems to be more cpu demanding. I'm now using the Georgian Hammer 6-2 mission for benchmarking because it seems to "hammer" my system the most and serves as a good worst case bench for tweaking (it has clouds too - which allows me to test for SLI induced flicker)

 

If you get bored, I'd be interested in your SLI vs. Non results using that mission.

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I suspect with your system that you are rarely getting cpu bottlenecked which allows your SLI to be better utilized. I have great SLI results in NTTR map but parts of the Caucasus map seems to be more cpu demanding. I'm now using the Georgian Hammer 6-2 mission for benchmarking because it seems to "hammer" my system the most and serves as a good worst case bench for tweaking (it has clouds too - which allows me to test for SLI induced flicker)

 

If you get bored, I'd be interested in your SLI vs. Non results using that mission.

 

As I have nothing else to do tonight, I tested the mission.

 

With SLI turned off,

FPS: 43

GPU usage: 99%

Screen_180224_215033.thumb.jpg.f11a1e2ed322da0d29d9cb7cf271cd1c.jpg

 

With SLI

FPS: 60

GPU usage: 80% both cards

I didn't observe any graphic anomalies.

Screen_180224_214657.thumb.jpg.5050651ee1f272957041c367d26005cb.jpg

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As I have nothing else to do tonight, I tested the mission.

 

With SLI turned off,

FPS: 43

GPU usage: 99%

[ATTACH]179828[/ATTACH]

 

With SLI

FPS: 60

GPU usage: 80% both cards

I didn't observe any graphic anomalies.

[ATTACH]179827[/ATTACH]

 

You have missed some vital information !! What graphics card are you using ?

 

Mizzy

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BabyPapa1, Thanks for sharing your results

 

I feel like I need to show some hard number results also to confirm the statements I made earlier that SLI DOES work but performance will vary if you have something else bottlenecking your framerates.

 

 

Specs are: i7-3930k, EVGA 580gtx 3Gb (x2), RAM:16Gb 2133Mhz . Test is run @1080p with DS, MSAA=2x, AF=2x, FXAA on and Fast Sync. SLI enabled by compatibility bits only (see above suggestion from BabyPapa1) Test is Georgian Hammer 6-2 mission because it is hard on my rig.

 

First photo is baseline (36 fps), showing test at "stock" cpu speed and sli disabled. GPU is at 99%. I am clearly limited by GPU

 

2nd photo confirms GPU is bottleneck because overclocking CPU has NO performance gain. Still at ~36 fps and GPU is at 99%

 

3rd photo shows SLI does work (53 fps, a 47% improvement), but gain is limited because I hit CPU bottleneck with "stock" speed. GPUs are underutilized at 85/78%

 

Last photo shows SLI working @ 96% utilization on both cards when I remove CPU bottleneck by overclocking CPU (now at 63 fps, a 75% improvement)

 

455530079_slitestresults2.thumb.jpg.bd2c2163f54f70fab9de54cf1c4b08cd.jpg

 

Under different test conditions, I can load the CPU so much that SLI shows no improvement (or worse)

 

Note: I reduced photo size to upload and Yes, I know my rig is very dated now. It was top shelf when I built it for the original A-10c standalone but with DCSW 2.5, I need as much extra performance as I can get by using SLI - hence this thread.


Edited by prccowboy
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BabyPapa1, Thanks for sharing your results

 

I feel like I need to show some hard number results also to confirm the statements I made earlier that SLI DOES work but performance will vary if you have something else bottlenecking your framerates.

 

 

Specs are: i7-3930k, EVGA 580gtx 3Gb (x2), RAM:16Gb 2133Mhz . Test is run @1080p with DS, MSAA=2x, AF=2x, FXAA on and Fast Sync. SLI enabled by compatibility bits only (see above suggestion from BabyPapa1) Test is Georgian Hammer 6-2 mission because it is hard on my rig.

 

First photo is baseline (36 fps), showing test at "stock" cpu speed and sli disabled. GPU is at 99%. I am clearly limited by GPU

 

2nd photo confirms GPU is bottleneck because overclocking CPU has NO performance gain. Still at ~36 fps and GPU is at 99%

 

3rd photo shows SLI does work (53 fps, a 47% improvement), but gain is limited because I hit CPU bottleneck with "stock" speed. GPUs are underutilized at 85/78%

 

Last photo shows SLI working @ 96% utilization on both cards when I remove CPU bottleneck by overclocking CPU (now at 63 fps, a 75% improvement)

 

[ATTACH]179834[/ATTACH]

 

Under different test conditions, I can load the CPU so much that SLI shows no improvement (or worse)

 

Note: I reduced photo size to upload and Yes, I know my rig is very dated now. It was top shelf when I built it for the original A-10c standalone but with DCSW 2.5, I need as much extra performance as I can get by using SLI - hence this thread.

 

excellent evidence ,)

 

basically, if SLI is configured right, all you need is to make your other link(s) in the chain just as powerfull...or you just dumped some big money for grey hair.

 

Which CPU do we use once we get mGPU with 2-4x 2080Ti ??? ehhhh LoL

 

We are steering into another bottleneck, again.

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Update about SLI. The graphic quality settings that I am currently using in DCS and NVI, One 1070 was not sufficient enough to do the job. At more demanding areas I was experiencing fps drop and flickering. So keeping in mind that I cannot afford a 1080 ti at the moment, spent some more time on the sli project and GOT IT TO WORKKK :lol:

 

The game is now running super smooth. Both VGAs are being utilized anywhere from 50% to 100% depending on the requirement. However, its not without some compromises. Once u load you first mission, You have to press alt + enter (ONLY ONCE) to make the sli work properly. Having done so, no matter u exit to main menu and load mission again, DO NOT press alt+enter againt or it will ruin the sli.

 

Secondly, pressing alt+tab to access anyother program while running dcs will RUIN SLI. So if u want to access any other program u have to exit DCS, do ur job and load dcs again.

 

I am attaching my NVI and DCS settings.

785041657_DCS2.5Settings.thumb.jpg.9ce4285f7f11aa43e033f011f173077a.jpg

NVI-1.thumb.jpg.42382073a3134e1fbd79b3817a8beeeb.jpg

NVI-2.thumb.jpg.b5aaa6853092b1602ca7ba3e118ce3bb.jpg

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It's seems many settings are working more or less... i didn't test in windowed mode, i will take a look.

 

Asus Rampage V Edition 10 / i9-9900k @5Ghz / 32Gb DDR4 @3200Mhz / Samsung 960 Pro M.2 / RTX2080ti / Vive Pro / ROG 3440x1440

 

You maybe saw I often edit my post. I want to tell you it's to correct spelling cause I only speak english a little and sometimes it's quite unclear... so forgive me !

 

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It's seems many settings are working more or less...

 

It seems the key is to change the SLI compatibility bits DX10+DX11. Different bits work to get SLI going but I still have best results using BabyPapa1's suggestion (above) which means that I also leave the "Nvidia predefined SLI mode on DirectX 10" on "AutoSelect" instead of forcing AFR2 like Drag80 does (with earlier versions of DCS I did use AFR2) - This seems to give me slightly better performance than forcing it. (Note: the other setting "Nvidia predefined SLI mode" is using "Force AFR2" but not the DX10 one)

 

i didn't test in windowed mode, i will take a look.

 

With w10 (and game mode on), I don't need to force FSE. The performance gains work in windowed mode (which is what I used for my screenshots above). I only need Full Screen Exclusive (L-Alt Enter), to force different vsync settings (other than Fast Sync).

 

I have a photo of my NVI compatibility bits above but maybe I will post a photo of all my settings later


Edited by prccowboy
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Both VGAs are being utilized anywhere from 50% to 100% depending on the requirement.

 

I still think that in the areas where you are dropping to 50% gpu utilization that you can increase your framerates and gpu usage by reducing your visible range

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I tried alt-enter but it introduces hard stutters for me.

 

I think each settings are very personnals cause of hardware.

I tried and retried and now I m very happy with this ones.

 

Also, since I have 32GB RAM I shutdown the pagefile and increase the preload radius to 300.000 in the "options.lua".

 

It works very good for me.

 

edit : I think G-sync is a problem for me too so I switched to fast sync and it works better

1.thumb.png.dcfcc3ee8888ea0c0201d709493de028.png

2.thumb.PNG.ffdb6667f6ba206e02cb2d147c765cff.PNG

3.thumb.PNG.5ed4ef29f75559043a79a59cecf990c0.PNG

 

Asus Rampage V Edition 10 / i9-9900k @5Ghz / 32Gb DDR4 @3200Mhz / Samsung 960 Pro M.2 / RTX2080ti / Vive Pro / ROG 3440x1440

 

You maybe saw I often edit my post. I want to tell you it's to correct spelling cause I only speak english a little and sometimes it's quite unclear... so forgive me !

 

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I tried alt-enter but it introduces hard stutters for me.

 

edit : I think G-sync is a problem for me too so I switched to fast sync and it works better

 

since you are using SLI, you might want to try "Smooth AFR" in vsync. It might help with some of the perceived stutter and combined with Fast Sync it doesn't really cap your max framerates

 

Here are my relevant NVI settings:

NVI1.jpg.ada8bfa035bd64985e105f6da43777af.jpg NVI2.jpg.0bf12ec5ce90e33f31a4ac9ce76676a5.jpg

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Which CPU do we use once we get mGPU with 2-4x 2080Ti ??? ehhhh LoL

 

heck, I'd be happy to get better mCPU utilization. When I get bottlenecked by max'ing only 2 cores of a 6C/12T cpu, I feel like I am wasting silicon (and $) Maybe future changes will start pushing my multi-core cpu. Previously I wasn't able to use SLI in DCS (an extra gpu wasted). Now I get to push both my gpu's to the limit. So I can only hope that one day I will get to push all my cpu cores. Until then I will just have to overclock to get better single core performance.

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since you are using SLI, you might want to try "Smooth AFR" in vsync. It might help with some of the perceived stutter and combined with Fast Sync it doesn't really cap your max framerates

 

 

Thanks it's a bit better with smooth afr.

 

I also deal now with clouds flickering. I tried your settings but the same... damned

 

Asus Rampage V Edition 10 / i9-9900k @5Ghz / 32Gb DDR4 @3200Mhz / Samsung 960 Pro M.2 / RTX2080ti / Vive Pro / ROG 3440x1440

 

You maybe saw I often edit my post. I want to tell you it's to correct spelling cause I only speak english a little and sometimes it's quite unclear... so forgive me !

 

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I also deal now with clouds flickering.

 

Here's another thread on the cloud flickering:

 

https://forums.eagle.ru/showthread.php?p=3409280

 

I'm uncertain if it is SLI related or not. With earlier versions of DCSW, I would see flicker with the "old" clouds but I could fix it with vsync. Now, I only get flicker occasionally and only with the bottom of the clouds but vsync has no effect. But because it is intermittent, I'm having trouble finding a solution.

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