No performance increase with SLI. Why?

[pardo]

I bought two GTX 260s recently and put them in the 750i motherboard. SLI is enabled in the Nvidia control panel. I have run various tests but am just not getting SLI performance. For example:
-I ran each card separately in a Crysis warhead benchmark and got avg 20ps (dx10, 1680x1050, 4xx AA, enthusiast).
-I ran the cards together in the benchmark and got avg fps of 26fps.
-I ran both cards with the sli bridge connected, disconnected and in the 1st and 2nd slots, no difference.
-Tried running different Nvidia control panel models (split frame SLI, alternate frame SLI), no difference.

I am running Vista 32-bit Enterprise SP1, 4GB of RAM, GTX 260x2, flashed to latest BIOS (I). Running latest beta Nvidia drivers too.

Can someone please help me? I'm really stuck! Thanks.

 

[heatlesssun]

Is SLI actually enabled? Do you see the SLI indicators in the game? At 1680x1050 you'll need to enable at least 4xAA as well to see a noticeable increase in performance.

 

[cannondale06]

what cpu do you have?

 

[bigdogchris]

I run at 1440x900 and I play Crysis on Very High settings around 35 FPS with SLI. If I disable SLI, it drops to around 20 fps. Other games though there is not much difference with SLI though.

pardo, do this. Make sure you have the SLI bridge installed properly. Uninstall the Nvidia drivers. Download and install the 180.43 drivers. When you reboot, it should say "this system is sli compatible, click here to enable". You click there, enable it, the screen goes black then it comes back up. Reboot at that point. You come back into windows and get the screen that says "SLI has been enabled" Don't mess with anything, don't 'tweak' anything. Start Warhead and go into the game and try again.

 

[cannondale06]

I run at 1440x900 and I play Crysis on Very High settings around 35 FPS with SLI. If I disable SLI, it drops to around 20 fps. Other games though there is not much difference with SLI though.

pardo, do this. Make sure you have the SLI bridge installed properly. Uninstall the Nvidia drivers. Download and install the 180.43 drivers. When you reboot, it should say "this system is sli compatible, click here to enable". You click there, enable it, the screen goes black then it comes back up. Reboot at that point. You come back into windows and get the screen that says "SLI has been enabled" Don't mess with anything, don't 'tweak' anything. Start Warhead and go into the game and try again.

sli for 1440x900? heck in most cases you will get zero increase and could actually get a decrease in performance due to overhead.

Im still curious as to what his cpu is.

 

[pardo]

Thanks for your posts. My CPU is an E8400 3.0GHZ OC to 3.8GHZ.

I just tried re-running the Crysis Warhead benchmark at 1680x1050, Enthusiast Settings, 4X AA. This is what I get:

One card: Min 11 fps, Avg 20, Max 27
SLI: Min 11, Avg 26, Max 41

So Avg FPS goes from 20 to 26 (30% increase). Is that SLI performance? From other users I thoguht SLI performance would scale 70%+. I think something is wrong...when I'm in game, I show SLI visual indicator and it shows the green bar filling up anywhere from 20% to 80%.

 

[heatlesssun]

Thanks for your posts. My CPU is an E8400 3.0GHZ OC to 3.8GHZ.

I just tried re-running the Crysis Warhead benchmark at 1680x1050, Enthusiast Settings, 4X AA. This is what I get:

One card: Min 11 fps, Avg 20, Max 27
SLI: Min 11, Avg 26, Max 41

So Avg FPS goes from 20 to 26 (30% increase). Is that SLI performance? From other users I thoguht SLI performance would scale 70%+. I think something is wrong...when I'm in game, I show SLI visual indicator and it shows the green bar filling up anywhere from 20% to 80%.

This looks about right I think at 1680x1050. Warhead scales ok in SLI but not as much as most games and 1680x1050 is really cramping the scaling.

 

[pardo]

For clarification, I am running GTX260 SC 216 edition x 2.

I had a friend of mine (same CPU OC) run the Crysis benchmark on the same settings (1680x1050, enthusiast, 4XAA, dx10) on his single GTX 280 FTW. He is getting the same performance as me basically!
His performance:
Min. FPS 18
Avg FPS 26
Max FPS 33

My avg. FPS was also 26! But I have 2 GTX260s...so clearly my SLI setup is not working properly...advice?

 

[kuyaglen]

Have you compared performance in other other games or 3dMark? Also try enabling the SLI bandwidth monitor. The benefit of SLI is more evident when running at higher resolutions. Though with SLI there is the option of having either a higher frames per second count or the ability to use SLI AA where there is no increase in fps but an increase in AA levels.

 

[vengence]

yeah, my advise would be to get a 24" monitor. Alternatly you could return one of the 260s

 

[Ogilvy]

I'm just curious Pardo...how much of that 4 GB of system is available in Vista 32-bit?

 

[koopaGG]

Enthusiast, DX10, and 4xaa? That sounds about right...

 

[rocketr2]

run it on windows xp dx9

 

[aekel]

I agree with the poster above. Definitely use DX9, I'm getting 42 average FPS with my OC'd 260 gtx at 1920x1200, no AA of course. But I still get in the 30's with 2x AA (can't remember exactly). Your numbers sound way low, go DX9 and get back with us.

 

[OmegaAvenger]

SLI is only about a 50-60% performance increase at best, and thats a high margin. Most SLI is either splitting the frame in half and having each card to half the frame or having each card do an alternate frame:

Card 1: frame one
Card 2: frame two
Card 1: frame three
etc.

Also both cards have an exact copy of each others ram so they can work on the same stuff.
They also have to talk to each other over the SLI bridge AND sometimes on the PCI-E bus (overhead), futhermore both cards are talking to your NB/CPU/RAM and thats another bottleneck.

Graphics processing isnt multi-threaded like normal code, hence the reason SLI doesn't scale as well as it should.

 

[GonzoP]

I agree with the poster above. Definitely use DX9, I'm getting 42 average FPS with my OC'd 260 gtx at 1920x1200, no AA of course. But I still get in the 30's with 2x AA (can't remember exactly). Your numbers sound way low, go DX9 and get back with us.

run it on windows xp dx9

Guys you don't buy GTX260's to run DX9, you don't play Crysis to play it in DX9. Its a system killer its true but scaling it back like that for higher frames is not going to improve the gaming experience.

 

[Zinn]

Guys you don't buy GTX260's to run DX9, you don't play Crysis to play it in DX9. Its a system killer its true but scaling it back like that for higher frames is not going to improve the gaming experience.

I run Crysis in DX9 on my GTX 280... I have it tweaked to look 95% as good as DX10 and it runs a hell of a lot faster. The main thing DX10 does in that game is slow it down to the point of being unplayable at decent quality settings.

 

[Naruto]

I wouldnt go SLI to play at 1680x1050 to begin with, would be up in the 1900x1200 ballpark.

 

[pardo]

Guys, I just ran the Far Cry 2 benchmark and I got 35 fps average for 1680x1050,4xAA,all settings max. My friend who has a SINGLE Gtx 280 gets 70 fps average! Something is VERY wrong with my setup...

P.S. i tried uninstalling and reinstalling the latest nvidia drivers like suggested but didn't help

 

[vengence]

SLI is only about a 50-60% performance increase at best, and thats a high margin. Most SLI is either splitting the frame in half and having each card to half the frame or having each card do an alternate frame:

Card 1: frame one
Card 2: frame two
Card 1: frame three
etc.

Also both cards have an exact copy of each others ram so they can work on the same stuff.
They also have to talk to each other over the SLI bridge AND sometimes on the PCI-E bus (overhead), futhermore both cards are talking to your NB/CPU/RAM and thats another bottleneck.

Graphics processing isnt multi-threaded like normal code, hence the reason SLI doesn't scale as well as it should.

50-60% is no the max for SLI. CoD4 is a clear example that near 100% scaling is possible. It is absolutely true that some games simply suck in thier scailing, but some don't.

 

[cannondale06]

Guys, I just ran the Far Cry 2 benchmark and I got 35 fps average for 1680x1050,4xAA,all settings max. My friend who has a SINGLE Gtx 280 gets 70 fps average! Something is VERY wrong with my setup...

P.S. i tried uninstalling and reinstalling the latest nvidia drivers like suggested but didn't help

your "friend" doesnt average 70 fps at 1680, 4x aa, and all max settings with a gtx280.

here they got 49fps for gtx260 sli on very high not ultra settings so your results are not far off. ultra shadows seem to take several fps over the very high setting just by itself. http://www.pcgameshardware.com/aid,..._and_CPU_benchmarks/?article_id=663817&page=3

 

[Roliath]

For comparison, here are my results. 1680x1050 here, DX10, rig in sig. 4xSSAA
Ultra High Settings

* Average Framerate: 48.62
* Max. Framerate: 72.63
* Min. Framerate: 35.52

Here's 8xSSAA

* Average Framerate: 46.22
* Max. Framerate: 70.73
* Min. Framerate: 36.37

 

[pardo]

MORE PUZZLING RESULTS!
I just ran Far Cry 2 benchmark with one card and with SLI. My performance DROPS with SLI!

One card:
Average Framerate: 36
Max. Framerate: 56
Min. Framerate: 25

SLI:
Average Framerate: 34
Max. Framerate: 49
Min. Framerate: 23


Does anyone know what I can do to resolve this? When I run each card separately, each performs the same.

 

[Brackle]

something I noticed

"I am running Vista 32-bit Enterprise SP1, 4GB of RAM, GTX 260x2, flashed to latest BIOS (I). Running latest beta Nvidia drivers too."


So first off you are not using your full amount of ram since you dont have 64bit OS...and you have 2 260gtx's which both have 896 megs of ram, so doesnt that take away even more ram you can use with your 32bit windows? which that would be 1.7gigs of Ram taking away from the limit of the 32bit OS?

Maybe he is running out of phyical memory when gaming?...Just a thought, I am probably wrong, but yea either way you are probably below 2gigs of overall ram you can use (i think)

 

[leetskeet]

call evga tech support...they're nice guys

 

[pardo]

Thanks for the tip - will call EVGA tech support now and see if they can help. This is very, very perplexing.

 

[Brackle]

Thanks for the tip - will call EVGA tech support now and see if they can help. This is very, very perplexing.

I would try a 64bit OS first before called EVGA.

Most games NEED 2gigs of ram nowadays, and if windows is showing less then 2gigs physical overall...well that could be your problem. Remember in SLI/crossfire the Memory isnt shared between the 2 Video video cards.

Shrug just a thought

 

[Brackle]

Check this thread out.

http://www.hardforum.com/showthread.php?t=1035670

Explains the 4gig limit with a 32bit OS

 

[kllrnohj]

Most games NEED 2gigs of ram nowadays, and if windows is showing less then 2gigs physical overall...well that could be your problem. Remember in SLI/crossfire the Memory isnt shared between the 2 Video video cards.

Heh, no they don't. All programs (on both 32-bit and 64-bit Window systems) are limited to 2GB of RAM max. So even if he can only use 3gb of the 4gb he has installed, it doesn't matter. The *only* game that I know of to ever actually hit the 2GB cap is Supreme Commander when dealing with a large map + 8 players + 1000 unit cap.

I just fired up Fallout 3 - ran around outside for a bit blowing stuff up, and it peaked at 650mb of RAM used. Granted, its not the most demanding game around, but that is still a far cry from the 2GB you claim that most games need.

 

[Brackle]

Heh, no they don't. All programs (on both 32-bit and 64-bit Window systems) are limited to 2GB of RAM max. So even if he can only use 3gb of the 4gb he has installed, it doesn't matter. The *only* game that I know of to ever actually hit the 2GB cap is Supreme Commander when dealing with a large map + 8 players + 1000 unit cap.

I just fired up Fallout 3 - ran around outside for a bit blowing stuff up, and it peaked at 650mb of RAM used. Granted, its not the most demanding game around, but that is still a far cry from the 2GB you claim that most games need.

Huh interesting, Just checked my fallout 3 while playing, and it was at 1.5gigs of memory being used.

You sure you got maxed out graphics 8x aa etc?...also depends on the resolution you are running at too.

P.S. Stalker CS uses over 2gigs of memory so its totally possible games can

 

[Ogilvy]

Heh, no they don't. All programs (on both 32-bit and 64-bit Window systems) are limited to 2GB of RAM max. So even if he can only use 3gb of the 4gb he has installed, it doesn't matter. The *only* game that I know of to ever actually hit the 2GB cap is Supreme Commander when dealing with a large map + 8 players + 1000 unit cap.

I just fired up Fallout 3 - ran around outside for a bit blowing stuff up, and it peaked at 650mb of RAM used. Granted, its not the most demanding game around, but that is still a far cry from the 2GB you claim that most games need.

I don't know about 64-bit Windows, but 32-bit Windows you can activate a 3Gb switch to allow programs to address larger than 2GB of system RAM. I've done it, with Supreme Commander and other games and it works quite well. Also, i've gone over 2 GB in Crysis Warhead in DX9 with my config file. Actually, I had the LARGE_ADDRESS_AWARE switch active on my Crysis.exe and the game still crashed when it hit an astounding 2.5 GB. I only have 3GB installed...I guess the other 512 MB or so were running the OS. No memory left = crash.

 

[kllrnohj]

Huh interesting, Just checked my fallout 3 while playing, and it was at 1.5gigs of memory being used.

You sure you got maxed out graphics 8x aa etc?...also depends on the resolution you are running at too.

P.S. Stalker CS uses over 2gigs of memory so its totally possible games can

AA and resolution won't affect RAM usage, just VRAM usage (there isn't any more data needed to be stored in system RAM for AA or higher resolutions - its still the same texture/game data ). But yes, it was max quality. Stalker CS can only use over 2gb of RAM if it has the LARGE_ADDRESS_AWARE switch activated, which I doubt it does.

Was that 1.5gb for the system or for the fallout 3 exe?

I don't know about 64-bit Windows, but 32-bit Windows you can activate a 3Gb switch to allow programs to address larger than 2GB of system RAM. I've done it, with Supreme Commander and other games and it works quite well. Also, i've gone over 2 GB in Crysis Warhead in DX9 with my config file. Actually, I had the LARGE_ADDRESS_AWARE switch active on my Crysis.exe and the game still crashed when it hit an astounding 2.5 GB. I only have 3GB installed...I guess the other 512 MB or so were running the OS. No memory left = crash.

Just ran through a Crysis level with the subtlety of a tank - chucking grenades everywhere, shooting down just about every tree I could find, blowing up every building, etc... and I had to work just to get it to crest 1.3gb. This is using the Ultra High config from here: http://www.incrysis.com/forums/viewtopic.php?id=17780

Also, the crash would only come if it tried to reserve past 3GB of RAM. The OS is happy handing out up to the absolute max. I assume you have a page file, in which case that last 512mb of RAM would not be a factor.

That said, the /3GB switch and LARGE_ADDRESS_AWARE flag are discouraged, *ESPECIALLY* for games: http://blogs.msdn.com/oldnewthing/archive/2004/08/06/209840.aspx

 

[Brackle]

AA and resolution won't affect RAM usage, just VRAM usage (there isn't any more data needed to be stored in system RAM for AA or higher resolutions - its still the same texture/game data ). But yes, it was max quality. Stalker CS can only use over 2gb of RAM if it has the LARGE_ADDRESS_AWARE switch activated, which I doubt it does.

Was that 1.5gb for the system or for the fallout 3 exe?



Just ran through a Crysis level with the subtlety of a tank - chucking grenades everywhere, shooting down just about every tree I could find, blowing up every building, etc... and I had to work just to get it to crest 1.3gb. This is using the Ultra High config from here: http://www.incrysis.com/forums/viewtopic.php?id=17780

Also, the crash would only come if it tried to reserve past 3GB of RAM. The OS is happy handing out up to the absolute max. I assume you have a page file, in which case that last 512mb of RAM would not be a factor.

That said, the /3GB switch and LARGE_ADDRESS_AWARE flag are discouraged, *ESPECIALLY* for games: http://blogs.msdn.com/oldnewthing/archive/2004/08/06/209840.aspx

yes it was fallout 3. and Iv seen stalker CS use over 2gigs alot....Also what resolution are you running in?...

Maybe its just Vista 64bit, I run everything in DX10 mode (if its a DX 10 game, which I know fallout 3 isnt)

But yea I ran fallout 3 8Xaa 15xAF, everything maxed at 1920X1200...

I dont even think your 4850 could handle that period. You would run out of memory for the video card.

link of stalker CS using over 2gigs http://www.hardocp.com/article.html?art=MTU2MSw2LCxoZW50aHVzaWFzdA==

So Just because you dont get up to 2gigs doesnt mean it does not happen.

I mean if you are going to have SLI 260's, wouldnt want to use 4-8X AA or higher at high res?...thats going to use up a good chunk of memory usage.

 

[Dangman]

With Crysis: Warhead on my gaming rig (Specs in sig), it took up 1.3GB of RAM during one run through of the entire game.

EDIT: Just realize that I didn't provide enough info:
- Monitor res was at 1440x900
- All settings on Mainstream (didn't feel like going to Gamer just yet)

 

[Ogilvy]

Put all your settings to Gamer, and try this cheap "Very High" config. file. Then type r_displayinfo 1. You'll be over 2 GB in no time. Texturesstreaming set to "0" seals the deal, but it runs oh so smooth.... DX10 will run 10 FPS slower and use about 200-300 MB less RAM, but it still goes over 2 GB easy.

Two things... you have to be in Vista (32-bit?) and you have to have @ least 1680 x 1050. XP or lower res. or any combination therof I don't know.


con_restricted=0
r_useedgeaa=2
r_sunshafts=1
e_detail_materials_view_dist_xy=4096

e_water_ocean_fft = 1
e_water_tesselation_amount = 10
sys_spec_Water = 3
q_ShaderWater = 3
r_WaterReflectionsQuality = 3
r_WaterUpdateDistance = 0.2

r_SSAO=1
r_SSAO_quality = 2
r_SSAO_radius = 2

q_renderer=3
r_colorgrading=1

q_shadershadow=1

r_TexturesStreaming=0
r_motionblur=4

That said, the /3GB switch and LARGE_ADDRESS_AWARE flag are discouraged, *ESPECIALLY* for games: http://blogs.msdn.com/oldnewthing/archive/2004/08/06/209840.aspx

You can discourage it all you want. I've been using it for months now...and it's perfect for the some of games I play. YMMV.


This is with r_texturesstreaming =0:



This is with r_texturesstreaming =1:

 

[kllrnohj]

yes it was fallout 3. and Iv seen stalker CS use over 2gigs alot....Also what resolution are you running in?...

Resolution is irrelevant. We aren't talking about VRAM here, we are talking system RAM.

Maybe its just Vista 64bit, I run everything in DX10 mode (if its a DX 10 game, which I know fallout 3 isnt)

Same.

I dont even think your 4850 could handle that period. You would run out of memory for the video card.

Also irrelevant... Although, since I have less VRAM than you, my system RAM usage could potentially be *higher* than yours, but not lower.

link of stalker CS using over 2gigs http://www.hardocp.com/article.html?art=MTU2MSw2LCxoZW50aHVzaWFzdA==

No where on that page does it every show/mention Stalker CS using over 2GB. The only thing it shows is that the *entire system* was using more than 2GB, which doesn't mean shit. Right now my system RAM usage is 2.16GB without any games running.

I mean if you are going to have SLI 260's, wouldnt want to use 4-8X AA or higher at high res?...thats going to use up a good chunk of memory usage.

No it won't. The level of AA and resolution will have next to zero impact on system RAM usage. AA is done on the card, not by the CPU+system RAM. Likewise, resolution only matters to the card, not to system RAM.

@Oglivy: I don't have Warhead, but the custom config I'm using for Crysis has all those same values applied, including texturestreaming = 0, and I only hit 1.3GB of RAM usage peak.

 

[Ogilvy]

@Oglivy: I don't have Warhead, but the custom config I'm using for Crysis has all those same values applied, including texturestreaming = 0, and I only hit 1.3GB of RAM usage peak.

Re-read my last post. I added a few screenies to show ya what I was talking about.

 

[kllrnohj]

Re-read my last post. I added a few screenies to show ya.

Try it without the /3GB switch - what happens then?

EDIT:
http://enthusiast.hardocp.com/article.html?art=MTQ4MCw3LCxoZW50aHVzaWFzdA==

The NVIDIA and 3870 cards both had system memory usage as high as 1.6 GB of RAM in DX9 mode. While in DX10 they were only around 1GB. So the higher the in-game settings in Crysis the more inefficient DX9 is.

I'm curious how much ram that same scene would use in DX10 (which is what I was using for my test)

 

[Ogilvy]

Try it without the /3GB switch - what happens then?

hmm....lemmie see.

 

[Ogilvy]

Try it without the /3GB switch - what happens then?

EDIT:
http://enthusiast.hardocp.com/article.html?art=MTQ4MCw3LCxoZW50aHVzaWFzdA==


I'm curious how much ram that same scene would use in DX10 (which is what I was using for my test)

Just as I suspected. I removed the LARGE_ADD._AW. flag from the Crysis.exe and I tried to load from the same point in those screenshots above. It wouldn't even load! It crashed with a "Crysis must shutdown" error. I'm tellin' ya, the /3GB swtich works...and works well.


I'll try it DX 10...but it'll be not much different (except for FPS). *edit* Just tried without the flag in DX10. Same thing...crash to desktop with "shutdown" error. DX10 will use a little less system RAM than DX9, but not that much less. 200 MB less is a generous average.