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[£%&)%#¤&@ SLI

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Freezer7Pro

Member
Joined
Apr 20, 2008
Location
FINLAND. EVERYTHING IS EXPENSIVE HERE.
I'm sure problems like these have been posted and solved many times before, but my searching hasn't really brought up anything that's helped me.

So I've got this semi-junk computer (4800+, NF570, 2x 8800GT 512), that I mainly run folding on, but sometimes use to play games with my friends. For the more recent games, I'd like to use both graphics cards, but, well, the computer doesn't agree. I've done everything from adding/removing the SLI bridge, swapping places on the cards, reinstalling the drivers, reinstalling Windows and so forth, to no success. When I turn on SLI, the only difference I can make out is that both graphics cards get warm instead of just one. 3DMark scores, game framerates and just about everything else remains 100% unchanged, like if nothing was changed.

Any ideas? Links that I've failed to spot are very welcome.

Thanks.
 

ThePerfectCore

Red Raccoon Dojo
Joined
Mar 1, 2002
Location
Texas
Not every game is SLI compatible, and I think your CPU is bottle-necking you. What are you trying to run?
 
OP
Freezer7Pro

Freezer7Pro

Member
Joined
Apr 20, 2008
Location
FINLAND. EVERYTHING IS EXPENSIVE HERE.
Not every game is SLI compatible, and I think your CPU is bottle-necking you. What are you trying to run?

Anything from 3DMark06 and Furmark to Crysis and UT3, so I think the applications not supporting SLI can be ruled out. I know the computer isn't exactly the greatest ever, but shouldn't there be at least some change in performance?
 
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elitesix

Registered
Joined
Apr 4, 2009
I'd try three different things:

1) Test if you are enabling SLI correctly: Enable the SLI Indicator option in the driver control panel and then load a game.

2) New video card drivers: Make sure to use a few of the various driver cleaner programs after uninstall of the old drivers but before the install of the new ones. Google for it, or check the forums on sites such as www.guru3d.com. You probably want to try 3 different driver versions these ways to see if there is a different.

3) Test for CPU-Bottlenecking. Up the resolution, AA, and AF to the highest possible with vsync disabled. Then check a game's fps with and without SLI. Also post your monitor's res; if you monitor is super low res this test may be useless.

Best of luck,
Elitesix
 
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Freezer7Pro

Freezer7Pro

Member
Joined
Apr 20, 2008
Location
FINLAND. EVERYTHING IS EXPENSIVE HERE.
Yep, SLI is activated alright. If I turn it on and launch Furmark, both cards get warm, even though the FPS is the same (or maybe even drops a little!) I just reinstalled the drivers for the nth time completely to no help.

I don't think the CPU is the bottleneck, as I get the same problems with all applications, irregardless of settings or resolution. Lowering the resolution/settings just makes it run faster like if I had a normally functioning single card.

I even tried changing one of the cards for a spare I had lying around, to no success.
 

EarthDog

Gulper Nozzle Co-Owner
Joined
Dec 15, 2008
Location
Buckeyes!
What PSU is powering that PC?

What resolution are you running it on? Furmark normally runs windowed and if you CPU is the bottleneck you wont see an improvement really.
 
OP
Freezer7Pro

Freezer7Pro

Member
Joined
Apr 20, 2008
Location
FINLAND. EVERYTHING IS EXPENSIVE HERE.
What PSU is powering that PC?

What resolution are you running it on? Furmark normally runs windowed and if you CPU is the bottleneck you wont see an improvement really.

The PSU is a Chieftec 500W, which should be OK, as it's steady at 11.9V with quite low ripple when the computer is loaded with FURMARK on both GPUs.

I'm running at 1280x1024 on my (two) ancient 17" monitors in extended desktop configuration. The problems won't go away if I remove one.

I still doubt that the CPU is the bottleneck, as I remember having SLI working just fine and giving me great results a year or so (and twenty odd reformats) ago on it.

@OnDborder: Yep, the latest BIOS for this rotten old MSI board is loaded since they stopped updating it.
 

EarthDog

Gulper Nozzle Co-Owner
Joined
Dec 15, 2008
Location
Buckeyes!
You can measure ripple? With software?

However I would be quite worried about a 500W Chieftec powering my SLI rig (unless its a delta made unit). Not a known good brand. With that in mind, if it can actually output its rated power, you SHOULD be ok. But.
 
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OP
Freezer7Pro

Freezer7Pro

Member
Joined
Apr 20, 2008
Location
FINLAND. EVERYTHING IS EXPENSIVE HERE.
You can measure ripple? With software?

However I would be quite worried about a 500W Chieftec powering my SLI rig (unless its a delta made unit). Not a known good brand. With that in mind, if it can actually output its rated power, you SHOULD be ok. But.

I used an oscilloscope. Bit of an electronics geek here ;)

The Chieftec is indeed a Delta. It's fine powering the computer even when I tried to put two GTX260s in it, so I think it should be able to do the 8800GTs without breaking a sweat. Especially as it's been on 24/7 folding for the last year or so, only stopping to replace a couple of caps on the mobo.
 
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jason4207

Senior Member
Joined
Nov 26, 2005
Location
Concord, NC
The PSU is a Chieftec 500W, which should be OK, as it's steady at 11.9V with quite low ripple when the computer is loaded with FURMARK on both GPUs.

I'm running at 1280x1024 on my (two) ancient 17" monitors in extended desktop configuration. The problems won't go away if I remove one.

I still doubt that the CPU is the bottleneck, as I remember having SLI working just fine and giving me great results a year or so (and twenty odd reformats) ago on it.

@OnDborder: Yep, the latest BIOS for this rotten old MSI board is loaded since they stopped updating it.

1280x1024 is a low resolution, and I'm almost positive you have a CPU bottleneck. And you definitely don't need 2 8800's to run that rez.

Try upping the CPU freq and see if there is any change in performance.
 
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Freezer7Pro

Freezer7Pro

Member
Joined
Apr 20, 2008
Location
FINLAND. EVERYTHING IS EXPENSIVE HERE.
1280x1024 is a low resolution, and I'm almost positive you have a CPU bottleneck. And you definitely don't need 2 8800's to run that rez.

Try upping the CPU freq and see if there is any change in performance.

Yes, the CPU is slow, but what's bothering me is that there is no change at all in performance when I enable/disable SLI. Take a look at 3DMark:

SLI.png

In the beginning of the first test, the CPU utilization hovers at around 30-40%, but yet the framerate sticks to 45-48 frames per second no matter what. I remember when SLI worked that I got up toward 80FPS on the first couple of seconds in that test.

I would overclock this computer a bit, if it weren't for the motherboard, which runs unstable before I even hit 210MHz FSB. I haven't bothered with getting SLI working properly since I'm running just such crappy monitors. What got me into trying to fix it is that I've ordered a (ultra-cheap) 24" 1080p monitor for it, for something one 8800GT won't do the trick anymore.
 

EarthDog

Gulper Nozzle Co-Owner
Joined
Dec 15, 2008
Location
Buckeyes!
I used an oscilloscope. Bit of an electronics geek here ;)

The Chieftec is indeed a Delta. It's fine powering the computer even when I tried to put two GTX260s in it, so I think it should be able to do the 8800GTs without breaking a sweat. Especially as it's been on 24/7 folding for the last year or so, only stopping to replace a couple of caps on the mobo.
GOod thing its a delta. Being used like that while shows its nice and stable, also degrades the PSU, though I dont think thats the issue here.

Can you run 06 or w/e at a higher resolution?
 
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Freezer7Pro

Freezer7Pro

Member
Joined
Apr 20, 2008
Location
FINLAND. EVERYTHING IS EXPENSIVE HERE.
GOod thing its a delta. Being used like that while shows its nice and stable, also degrades the PSU, though I dont think thats the issue here.

Can you run 06 or w/e at a higher resolution?

Oh, it's just a matter of time before the China-caps in it are history. I think it's got CapXon on the primary and some other horror on the secondary. I'm amazed that it's actually held up for this long without a recap :cool:

And I can't really run anything at a higher res before I get my new screen later this week.
 

Shadowmonk

Member
Joined
Mar 18, 2008
SLI will not show much improvement @1280 x 1024. At this resolution the GPU does only a small portion of the work in games, if you change over to a higher resolution monitor it would be the best way to test if the setup is affected.
 
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Freezer7Pro

Freezer7Pro

Member
Joined
Apr 20, 2008
Location
FINLAND. EVERYTHING IS EXPENSIVE HERE.
SLI will not show much improvement @1280 x 1024. At this resolution the GPU does only a small portion of the work in games, if you change over to a higher resolution monitor it would be the best way to test if the setup is affected.

Alright, I got my new monitor today. I'll see if there's a difference when I bring it to the computer on Monday.