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Crossfire = Worse Performance?

S

Silent Ricochet

n00b
Joined
Feb 15, 2008
Messages
60
Hey guys, just got my new HD4850 in the mail today and decided to throw it into my computer and crossfire it with my other HD4850.

Here's the problem. I've installed it correctly, installed the latest ATI Drivers (10.11), and before I tried it out on some games, I checked out my setup on GPU-Z...

When looking at GPU-Z It states that my first video card is only running at:

PCI-E 2.0 x16 @ x8 2.0

And my second card is running at:

PCI-E 2.0 x16 @ x4 2.0

Company of Heroes saw almost no performance games during the benchmark. Half Life 2 Episode 2 on the other hand ran ridiculously well on maxed settings, very impressed. But the major problem comes into play on Battlefield Bad Company 2, which runs around 30FPS, which is what caused me to look at GPU-Z in the first place. <--- FRAMERATES PROBLEM HAS BEEN FIXED

I've spoken to ATI over the phone, they were unable to help, and Gigabyte said they'd "call me back".... So I turned to you guys. My motherboard specs state that one slow should be running at x16, the other at x8, so why are they running at half their speeds?

Quick Computer Specs:

CPU: AMD Phenom II x720 BE overclocked to 3.2GHz, 4th core unlocked (stable)
Motherboard: Gigabte GA-MA790X-UD4P
Memory: G.Skill F2-8500CL5D-4GBPK 4GB Dual Channel (PC2-8500)
Video Card 1: ASUS EAH4850 512M
Video Card 2: HIS H485FM512H HD 4850 iCooler
 
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The PCI-E lanes won't affect performance, the most difference you might see would be 1fps at the absolute MOST.

HardOCP just ran articles on this recently, check them out if you are concerned.

I'd make sure you installed the Catalyst Application Profiles which configure Crossfire.

http://www.rage3d.com/cap/
 
What power supply do you have?

When I first tried crossfire with my 4830s, it was slower than when running just one in most games.

Turns out my measly Earthwatts 500 wasnt up for the power draw. lol
 
I'm running a Corsair GS600 600W Power Supply. The resolution i'm running in all games and on desktop is 1680 x 1050. Settings in Battlefield Bad Company 2 are all high, AA and filtering at 4x and HBAO = on.
 
Are the cards exactly the same? Check the bios on the cards and see what they are, then tell us here. Also see if there is a mobo bios update for your board.

I would do a clean windows install on an old HDD if you have one, just for testing.

Also a long shot is to juggle the power cables around on the cards, I know thats a long shot, but I have come across that as an issue in the past.
 
CMD said:
Are the cards exactly the same? Check the bios on the cards and see what they are, then tell us here. Also see if there is a mobo bios update for your board.

I would do a clean windows install on an old HDD if you have one, just for testing.

Also a long shot is to juggle the power cables around on the cards, I know thats a long shot, but I have come across that as an issue in the past.
Click to expand...

Nah, the cards are different.

The Asus card Bios version is: 011.003.000.000.029117
The HIS Card Bios Version is: 011.022.006.000.000000

funny thing is, I downloaded that CAP thing that the first poster suggested and my Framerates almost doubled in Battlefield BC2. So the crossfire is certainly helping performance, but I'm still curious as to why my second PCI-E port is running at x4. Both of the ports should be running at x8 in CF mode.
 
Sorry bro, but you're out of VRAM. It's just a bad idea to run MGPU with half a gig these days. Your video ram doesn't double to 1gb just because you have 2 512mb cards.
 
rUmX said:
Sorry bro, but you're out of VRAM. It's just a bad idea to run MGPU with half a gig these days. Your video ram doesn't double to 1gb just because you have 2 512mb cards.
Click to expand...

The framerates problem has been fixed with CAP3 from ATI, I guess it's a crossfire profile for the drivers to refer too. Avg FPS went from 30 to 75. :D
 
Silent Ricochet said:
Haha thanks so much dude. BC2 runs awesome now. A Flicker here and there, but I hear thats a common problem. No big deal though.

Any idea why my second port is still only running at x4?
Click to expand...
NewEgg says this about the PCI-E layout on your board:

"1 x PCI Express x16 slots, running at x16 (PCIEX16_1)
1 x PCI Express x16 slots, running at x8 (PCIEX8_1)

For optimum performance, if only one PCI Express graphics card is installed, be sure to install it in the PCIEX16_1 slot. The PCIEX8_1 slot shares bandwidth with the PCIEX16_1 slot. When PCIEX8_1 is populated with a PCI Express graphics card, the PCIEX16_1 slot will operate at up to x8 mode."

Do you have a sound card, NIC or RAID card or something in the PCI-E 1x slot?

You really don't need to worry though.

http://www.hardocp.com/article/2010/08/25/gtx_480_sli_pcie_bandwidth_perf_x16x16_vs_x4x4/

"The results are actually a bit shocking to us to be honest. We weren&#8217;t so surprised that in the previous evaluation x8/x8 did not cause any differences at 2560x1600 but did at 5760x1200. However, we thought certainly at x4/x4 PCIe 2.0 mode there would be some kind of a bottleneck at 2560x1600, but the results have proven otherwise. Even with all the data that GTX 480 SLI is pushing across the PCIe bus, x4/x4 is NOT a bottleneck in a single display setup at 2560x1600 with AA enabled. The only game to show us any difference was AvP, but it did not affect the gameplay experience. Therefore, if you are on an aging PCIe 1.X system at x8/x8 mode (equivalent to PCIe 2.0 x4/x4) on a single display fear not, you are not holding back the performance of GTX 480 SLI or we guess with any CrossFireX or SLI configuration."

That is with SLI GTX480s running 2560x1600. You are running much slower video cards at a much lower resolution so the amount of data needed to be passed through the PCI-E bus is far less, making this even less of a concern for you.
 
Good post by Rizen, besides that make sure you have the newest bios flashed on your motherboard as suggested before. Check all your bios settings and make sure everything there is good too.
 
Thanks guys, all of you. Especially Rizen, you're awesome man.

I'm not sure what I did, but I reinstalled my ATI drivers after using driver sweeper in safe mode, and cleaned both slots and crossfire connections with alcohol. Restarted, and Lo and behold both cards were running correctly at x8. Just tested it really quick on BC2. Runs great, little bit of a stutter here and there, some missions flickered, but ATI was supposed to address that issue with the latest Driver release, so I'm thinkin it's just a driver problem. I'll see how things play out in the next couple of days.
 
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