Please help with new Crossfire setup! - update with resolution

[The Sauce]

Ok, after voluminous amounts of research, I found the issue. It's the motherboard. My P7P55D-E chokes down PCI-E from 16x (single card) to 4x (dual cards). Read several articles recommending avoiding Xfire with this PCIE config. That would explain why my FPS were down with both cards in even with crossfire disabled.

So it seems I either upgrade my mobo or send the card back. The answer is still - send the card back. Otherwise this becomes a $400 upgrade for crossfire and that is not what I had in mind. On the other hand I could keep it around for my next CPU/Mobo upgrade in a year but I have a feeling the 5850 will be obsolete by then.

 

[Kenmitch]

It's the motherboard. My P7P55D-E chokes down PCI-E from 16x (single card) to 4x (dual cards).

That sucks! Whenever I'm looking at MB's that's one of the first things I look for. Never did crossfire or sli yet but I like to keep my options open.

You should move your statement about being your MB choice to the first post....No need to add fuel to the fire

 

[Wuzup101]

You can just do the workaround using radeon pro for rift (use radeon pro to enable AFR when rift is active). You should then get crossfire scaling and avoid the 3d model glitch. The current problem with rift is that when you click on a player / yourself / look at yourself in the character viewer card usage goes way up and FPS drops to crap. You have to alt+tab to fix it. AFR will take care of the problem, but your game map will flicker. It's anoying... but it's another option. Hopefully the dev team will have it sorted out in short order.

 

[Termie]

I was going to mention the 4x PCIe lane earlier, but it really wouldn't account for negative scaling. It might be enough to make two stock clocked 5850s perform like one highly overclocked one, but I doubt it would do so in most situations. I wonder if there's something else going on in BC2.

 

[Spikesoldier]

i had this issue at first with my p55 board. even though they were in the correct slots, all i did was simply re-seat the vga cards and that fixed everything and allowed 8x/8x operation.

i would also check your mainboard to make sure that you are plugging the vga cards in the correct slots. my board is 16x 8x 4x.

with one card, put in 16x slot and runs at 16x.
with two cards, put in 16x and 8x slot and runs at 8x/8x.
with three cards, put in all and it runs 8x/8x/4x.
if i put the two into the 16x and the 4x, i get 16x/4x.

basically your second card is running of the secondary 4x link.

 

[Termie]

i had this issue at first with my p55 board. even though they were in the correct slots, all i did was simply re-seat the vga cards and that fixed everything and allowed 8x/8x operation.

i would also check your mainboard to make sure that you are plugging the vga cards in the correct slots. my board is 16x 8x 4x.

with one card, put in 16x slot and runs at 16x.
with two cards, put in 16x and 8x slot and runs at 8x/8x.
with three cards, put in all and it runs 8x/8x/4x.
if i put the two into the 16x and the 4x, i get 16x/4x.

basically your second card is running of the secondary 4x link.

His board has two slots, and they operate at 16x/4x: http://www.newegg.com/Product/Produc...82E16813131620

That being said, this is why I don't think the 4x slot is causing such terrible scaling: http://www.tomshardware.com/reviews/pcie-geforce-gtx-480-x16-x8-x4,2696-9.html. Depends on the game - COD gets hit bad, but Crysis barely budges on the 4x slot.

OP - what was GPU usage for each card in BC2 according to Afterburner/GPUz?

 

[Termie]

FYI - new article on crossfire scaling, including 16x/4x scaling: http://www.tomshardware.com/reviews/pci-express-scaling-p67-chipset-gaming-performance,2887-10.html.

This is why I don't think your motherboard is the main culprit. If you're already returned the card, I guess it doesn't matter, but if you feel like trying again, it looks like you should be able to get more performance out of it.

 

[LiuKangBakinPie]

Ok, after voluminous amounts of research, I found the issue. It's the motherboard. My P7P55D-E chokes down PCI-E from 16x (single card) to 4x (dual cards). Read several articles recommending avoiding Xfire with this PCIE config. That would explain why my FPS were down with both cards in even with crossfire disabled.

So it seems I either upgrade my mobo or send the card back. The answer is still - send the card back. Otherwise this becomes a $400 upgrade for crossfire and that is not what I had in mind. On the other hand I could keep it around for my next CPU/Mobo upgrade in a year but I have a feeling the 5850 will be obsolete by then.

that bandwith is still enough
http://www.hardocp.com/article/2010/08/25/gtx_480_sli_pcie_bandwidth_perf_x16x16_vs_x4x4

 

[LiuKangBakinPie]

Check your BIOS settings. In BIOS > Advanced > Chipset >

Memory Remap Feature [Enabled]
Initiate Graphic Adapter [PEG/PCI] <-- you have this?!
PEG Port Control [Auto] <-- you have this?!
PEG Port Force x1 [Disabled] <-- you have this?!
Then, back in Windows, did you install the latest http://downloadcenter.intel.com/Detail_Desc.aspx?agr=Y&DwnldID=18494&lang=eng

 

[The Sauce]

Check your BIOS settings. In BIOS > Advanced > Chipset >

Memory Remap Feature [Enabled]
Initiate Graphic Adapter [PEG/PCI] <-- you have this?!
PEG Port Control [Auto] <-- you have this?!
PEG Port Force x1 [Disabled] <-- you have this?!
Then, back in Windows, did you install the latest http://downloadcenter.intel.com/Detail_Desc.aspx?agr=Y&DwnldID=18494&lang=eng

Of those options, the only one I have in my BIOS is Memory Remap and it was already set to [Enable].

For the Intel Inf file, I could not find the correct one for my motherboard. The one you linked does not include the P55 chipset and a search of the Intel site did not turn it up. Last thing I want is to download the wrong file and screw other things up in the process.