Low FPS and low GPU usage in BF3 with two 7970Ghz Edition Cards?

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jedinegotiator

jedinegotiator

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Apr 2, 2011
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I just upgraded, or so I thought, from two 7950s to two 7970Ghz Cards. I have been running some bench marks and I have not been pleased. In Battlefield 3 on Caspian Border I used to get about 100-110FPS with my two 7950s. With my two new 7970Ghz Edition Cards I am getting pretty much the same FPS and only about 60% GPU Usage. All of this is at 1920x1080. My 7950s were always right around 100% usage.

Now there is a couple things I want to mention about things that have changed to maybe give you a clue of why this may be happening.

First I am using two different brand cards now which shouldn't matter. The first is a Gigabyte 7970 clocked at 1100Mhz. The second is a Sapphire clocked at 1050Mhz. I have verified both cards are good. When running either card alone they get 100% usage and 90-100FPS. From other peoples benchmarks I should be getting at least 150+ FPS in a Cross fire configuration.

The next thing I wanted to let you guys know is that one card is at x16 speed and the second is at x4 speed. This is a change. With my 7950s I was running at x16 and x8 but the 7970s are so big that I used the x4 slot to give them more breathing room. Now I expected this to cause my second 7970 to be bottlenecked but that doesn't explain why my x16 7970 is also getting very low usage.

Here is a screenshot of my afterburner stats while in BF3:
http://filesmelt.com/dl/7970_X-Fire1.png
FPS is at 106
GPU 1 Usage is at 62%
GPU 2 Usage is at 76%

So my question is why is this happening? Could it be because my second card is at an X4 link speed? If it is I just don't understand why it would cause my first GPU Usage to be low. Heck, my second GPU is getting more usage than my first and the first is at x16! I am so confused...
 
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iam2thecrowe
well, to determine a cpu bottleneck, turn the resolution and AA down, try 720p and no AA, leave all other settings as is as they can affect cpu performance too, if you see no significant increase in fps, then your cpu bottlenecked. What exact motherboard do you have? does it have latest BIOS? latest AMD beta drivers? dry driversweeper in safe mode to remove all old drivers and registry entries and clean install the latest driver again. If you have the frame pacing option enabled in the driver, that can reduce gpu useage and increase cpu overhead, you could try disabling it but it negatively impacts your perceivable performance at the monitor, but might give you more fraps measured fps and gpu useage. Sometimes Crossfire doesnt work its...
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jedinegotiator

jedinegotiator

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Ok so I just moved the slots. They are right up against each other now. The first card is reporting x8 speed. The second is reporting x8 as well. I run played Battlefield again and this time I was getting 110-120FPS on average. GPU1 usage was at 69% and GPU2 usage was at 72%. Still not what I would like to see but it was a little better I guess. Could x8 speeds be limiting these cards? I was under the impression that the performance drop from x16 to x8 was very little.
 
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iam2thecrowe

iam2thecrowe

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Jul 4, 2010
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probably a cpu bottleneck. what cpu do you have? Also, are you using a 120hz monitor? if your using a 60hz monitor, any frames per second over 60 are completely wasted, 2 parts or more of a frame will appear at once on your screen for one refresh cycle of your monitor. Better off upping AA or something and getting better visual quality at the cost of some of the fps that are now wasted.
 
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jedinegotiator

jedinegotiator

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I am already on ultra settings so AA is maxed. I am using a 4770K so I would hope that the CPU is not a bottleneck. But like I said both cards are running at x8 speeds. From what I have heard other people say no GPU maxes out the x8 speed and x16 is not needed.

I do have a 120Hz monitor, but even if I didn't I would still want to be able see that the power of the cards I have are working. I get an average of 100FPS on BF3 with a single card and with another card I get just 10 frames more. That should not be...
 
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iam2thecrowe

iam2thecrowe

Glorious
Jul 4, 2010
10,591
21
44,965
well, to determine a cpu bottleneck, turn the resolution and AA down, try 720p and no AA, leave all other settings as is as they can affect cpu performance too, if you see no significant increase in fps, then your cpu bottlenecked. What exact motherboard do you have? does it have latest BIOS? latest AMD beta drivers? dry driversweeper in safe mode to remove all old drivers and registry entries and clean install the latest driver again. If you have the frame pacing option enabled in the driver, that can reduce gpu useage and increase cpu overhead, you could try disabling it but it negatively impacts your perceivable performance at the monitor, but might give you more fraps measured fps and gpu useage. Sometimes Crossfire doesnt work its best with certain settings so you might have to fiddle with the AA settings, you could also be filling the vram on your cards if you use too much aa, and your performance will then be limited by your system memory speed as once vram is full, it uses system ram.
 
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