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BF3 - Single Radeon 6850 runs better than 2x 6850 in Crossfire

Last response: in Video Games
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June 21, 2012 1:21:49 AM

All,

I am having performance issues in BF3. I have 2x Gigabyte HD 6850 GVR685OC-1GD Radeon 6850 video cards in Crossfire mode. I will post the rest of my system specs below.

Basically, Battlefield 3 runs better with Crossfire disabled. It is smooth as silk when running at 1920x1080 on a single 6850. But as soon as I enable Crossfire mode, my FPS drops pretty low when looking over the battlefield (long distance) or when I get into a lot of action with smoke/fire.

I have tried numerous things. Even wiping and reformatting my system. I first tried using the latest drivers for my motherboard (Gigabyte GA-MA790XT-UD4P) from their website. Same performance issues with Crossfire.
I've tried getting the latest individual drivers for each piece of hardware in my system (chipset, graphics, audio, NIC) - even tried AMD Catalyst 12.6 Beta.
Same performance issues with Crossfire.

I've tried AMD 12.6 CAP profiles for BF3.
Same performance issues with Crossfire.

A single 6850 runs much smoother than 2x in crossfire, which I would definitely not expect. I wouldn't think it would be my CPU since the game runs great with Crossfire disabled, unless the CPU isn't enough to push 2x 6850's? I am very tempted to just rip the second 6850 out...

The CPU temps hit up to the low 50's. The GPU temps hit low to mid 50's. The CPU idles around 37*C. The GPUs idle around 40*C.

> Mainboard : Gigabyte GA-MA790XT-UD4P

> Chipset : AMD 790X

> Processor : AMD Phenom II X4 945e @ 3000MHz

> Physical Memory : 8192MB (4 x 2048 DDR3-SDRAM )

> Video Card : AMD Radeon HD 6800 Series (two 6850's)

> Hard Disk : Western Digital WD10 EALX-009BA0 SATA Disk Device (1000GB)

> DVD-Rom Drive : ELBY CLONEDRIVE

> DVD-Rom Drive : HL-DT-ST DVD-RAM GH22NS30

> Monitor Type : Toshiba TOSHIBA-TV - 40 inches

> Monitor Type : Asus ASUS VH242H - 23 inches

> Network Card : Intel 82574L Gigabit Network Connection

> Network Card : Realtek Semiconductor RTL8168/8111 PCIe Gigabit Ethernet Adapter

> Operating System : Windows 7 Professional Professional Media Center 6.01.7601 Service Pack 1 (64-bit)

> DirectX : Version 11.00

Power Supply - Corsair 650w

GPU-Z:
http://gpuz.techpowerup.com/12/06/20/g2s.png (first screenshot I took)
http://gpuz.techpowerup.com/12/06/20/dmf.png (second screenshot I took after closing/reopening GPU-Z)
http://gpuz.techpowerup.com/12/06/20/7kr.png

What is going on?
June 21, 2012 3:16:47 AM

Enable crossfire and do a screenshot of the 1st card with GPU-Z, and select the 2nd card in GPU-Z (there is a little arrow on the bottom and will say the same thing) and take a screenshot of it.

It looked like one of your cards is in a PCI-E x8 1.1 slot. Although little, the crossfire will not work properly if both cards are not using the same specs for a PCI-E slot.

like a x16 2.0/x16 2.0, or a 8x 1.1/8x 1.1.

Let me know when you update the screenshots.
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June 21, 2012 3:22:25 PM

fantastik250 said:
Enable crossfire and do a screenshot of the 1st card with GPU-Z, and select the 2nd card in GPU-Z (there is a little arrow on the bottom and will say the same thing) and take a screenshot of it.

It looked like one of your cards is in a PCI-E x8 1.1 slot. Although little, the crossfire will not work properly if both cards are not using the same specs for a PCI-E slot.

like a x16 2.0/x16 2.0, or a 8x 1.1/8x 1.1.

Let me know when you update the screenshots.



http://gpuz.techpowerup.com/12/06/20/efv.png
http://gpuz.techpowerup.com/12/06/20/2qz.png
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June 21, 2012 8:19:54 PM

Now are both cards using the same 12.6 BETA drivers? it seems that one of them is 12.6
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June 21, 2012 9:02:06 PM

fantastik250 said:
Now are both cards using the same 12.6 BETA drivers? it seems that one of them is 12.6

They should be. When I looked at the properties under Device Manager, the driver version is the same on both AMD Radeon 6850 devices listed.
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June 22, 2012 1:58:19 AM

Does the crossfire issue happen with other games other than BF3?
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