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Really puzzeled about an SLI issue in BF3 with 580's.. help please.

Last response: in Graphics & Displays
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November 3, 2011 4:56:26 PM

So I recently received my second GTX 580 in the mail. Was excited to plug it in and try out a few games in SLI, specifically BF3..

What followed and is still following is hours of stress and confusion.. For some reason my cards will not run BF3 at near max usage.. around 50/50% a card resulting in TERRIBLE fps, by terrible I mean like 60ish on medium/high.. Hell I get better fps with just 1 580.

The weird thing is that in an empty game my usage substantially goes up 90% or so on each card, and along with that my FPS goes up into the 110/120's which is what it should be.. The second I join a game thats larger than 10v10 usage will drop to 50/50% again and the terrible fps begins..

I've tried running driver sweeper in safe mode multiple times, so its definitely not a driver issue.. I've also tested the SLI setup in Bad Company 2 with everything maxed out msaa x 8 and my frames are beautiful there 130-140+ almost constantly so Im starting to doubt this is hardware related..

my specs:
Evga GTX 580 x2
Crosshair V Formula
8 GB DDR3 1600
AMD 1090T sitting at 3.9 ghz
Corsair Force 3 SSD

I've had a few people telling me its my cpu thats making a bottle neck but for some reason Im having a very hard time believing it.. Anyone have any idea what it could be? Could it truly be my cpu..
November 3, 2011 9:13:32 PM

CPU bottlenecks shouldn't be that restrictive. You seem to have tons of CPU power.

BF3 has just been released and EA games in my opinion are always buggy and have bad performance upon release. BF3 has a new graphical engine that I doubt is optimized yet. BC2 took more then a year to solve most of its performance issues.

In Sli I havn't seen many game utilize near 100% of both cards at a time. Although it happens occasionally.
Sometimes my two GTX 560Ti's in SLi run at about 80%/80% together and sometimes at 50%/50% for the same map/scenario/game.

I read that the newest nvidia driver has eliminated alot of performance issues with BF3. Try that.
Try leaving all nvidia driver settings at default and change them one by one to measure any differences. Shut off Ambient Occlusion and anti aliasing completely. Note the difference. I had 580's in SLi as well and got poor performance. I got the 560 ti's instead and with AA enabled I got no worse performance. Strange cause I thought 580's were supposed to be, ooh i dunno, more powerful.

Anyway, if you have tried all obvious stuff like that, then move on to hardware config. For me, Hyper threading or hyper transport for you, makes my games run like ***, BF included. Try shutting it off in BIOS along with trying other pci-e slots. I actually placed my second GTX 560 in the third slot that only runs at x8 speed and it boosted the performance and smoothness of my games. Benchmarks I've read show no real performance loss from x8 slots anyway, plus your first card will be able to breath. I dropped 20 degrees in first GPU by doing this. Make sure that if your power supply has dedicated rails for GPU1, GPU2, etc, that for example your primary GTX 580 doesn't share connections to the PSU for GPU rail1 and GPU rail2. I have tried mixing those rails for GPU 1 and GPU 2 and have lost performance in the past.

I might buy BF3, if I encounter similar issues I'll post.
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a c 75 Î Nvidia
November 3, 2011 9:25:35 PM

There is a new driver that supposedly "fixes" the SLI problem in BF3. However, I also saw a few threads where peeps had to uninstall their "performance enhancing software" (Read Afterburner, SmartDoctor, etc).....note, you didn't have to be using it to OC the cards, it simply had to be installed.
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November 3, 2011 9:25:51 PM

I very much doubt it's your CPU, a 1090T at 3.9ghz should be plenty. Out of curiosity though, run task manager while playing and alt+tab to check what your CPU usage is on each core during 50%/50% GPU usage.
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November 3, 2011 9:49:26 PM

Update: I forgot to mention that what may seem like a cpu bottleneck may simply, and most likely, be that your video cards are not utilizing their full potential. The only way to really get you GPU's to work at full throttle is to manually set anti aliasing high and with supersampling enabled, ambient occlusion, gamma corection, anisotropic filtering high...essentially near max our your settings in control panel and in game and I'm sure you'll notice the GPU usage rise to 90% plus.

The thing is that just because you have 580's, it doesn't mean a game will use every corner of the chip all the time. There are many areas on that die that are responsible for different things and they are not all always utilized to the max all the time. You can't ask an area of the GPU that is responible for one task to perform another only because its not that busy. So try demanding more from the gpu's and see how it affects GPU usage and overall performance.

A really strange thing I've noticed is that if I enable supersampling, my frames decrease a tad but the game runs much smoother.

So you might now be wondering why you get high gpu usage from a single card on the same game. I suppose that might all have todo with how the driver is delegating traffic to balance the load between the two cards for specific tasks in the rendering process. Even the game engine itself has limits for how how data it can handle, which is why I believe its all up to the drivers and game it self.

Also, what Jack mentioned about Afterburner/rivetuner, I can confirm that that software has def. affected the performance of my drivers many times, even when I just installed it and didnt touch any settings. Overclocking rarely gives you much of a true performance boost anyway before you start reaching insane temps on GTX 580. If you have it, delete it.
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November 5, 2011 8:23:24 AM

Thought I'd add a reply and an update.. To my surprise it did in fact end up being my 1090T that bottle necked me.. I've been meaning to switch to intel and Microcenter is having a great sale, i2500k for 179.99 + any p67 board $60 off, so I went ahead and picked up a 2500k along with a sabertooth p67.. Overclocked the 2500k to a mild 4.0 ghz and right away I'm getting proper 90%+ usage with nice framerates.
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November 5, 2011 8:29:32 AM

Wow, your 1090T was really bottlenecking you? Very odd...
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November 5, 2011 6:20:02 PM

gmcizzle said:
Wow, your 1090T was really bottlenecking you? Very odd...


Yeah I found it more then odd, but it ended up being true.
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