270x's in crossfire performing way worse than single card?

[badfish2162]

Hi,
So as the title says, I'm getting worse performance out of 2 of my 270x's in crossfire than I am with a single 270x, by a lot. I'm running the latest drivers: 14.12 and have had the same issue with previous drivers as well. So far I've tested this out on Metro Last Light (where my frames drop from around 40-50 avg to around 15-25 when activating the second card) Planetside 2 (which isn't as drastically poor as Metro in the sense that the fps isn't cut in half w/ the second card but is still lower) and most recently I ran the Unigine Valley Benchmark which gave me 59.6 fps average with a score of 2493 with a single card and 33.4 fps average and 1398 score with the second card enabled. It seems almost as though the second card is running at half speed (pci 4x?) and is bottlenecking the other card, but in the mobo manual the slot I've got it in is listed as pci-e 16x. I'm running a fresh install of Windows 7 64bit and here are my system specs:

Asus Z97-AR
i7-4790k @ stock
8gb ram
(2) 270x sapphire
700 watt OCZ

Has anyone had a similar issue with any of this hardware? Can anyone shed any light on what the issue may be given the info I've provided? If I've left anything out let me know and thanks in advance for any help.

 

[clutchc]

Your're not also using the other slots are you, or have a drive in the M.2 slot?

 

[badfish2162]

All other PCI slots are unoccupied. Nothing in the M.2 slot either.

 

[clutchc]

If the cards are in the correct slots, they should each be at x8 lanes. Try the 2nd card alone in the first slot to be sure the card is OK. See if it matches the FPS of the 1st card.

Does CCC show that CF is enabled?
Are you using the bridge? Can you try it w/o the bridge and see if anything changes? Or try another bridge.
Is the monitor plugged into the first card? (normally, it shouldn't matter)

 

[roadrash151]

Hi,
So as the title says, I'm getting worse performance out of 2 of my 270x's in crossfire than I am with a single 270x, by a lot. I'm running the latest drivers: 14.12 and have had the same issue with previous drivers as well. So far I've tested this out on Metro Last Light (where my frames drop from around 40-50 avg to around 15-25 when activating the second card) Planetside 2 (which isn't as drastically poor as Metro in the sense that the fps isn't cut in half w/ the second card but is still lower) and most recently I ran the Unigine Valley Benchmark which gave me 59.6 fps average with a score of 2493 with a single card and 33.4 fps average and 1398 score with the second card enabled. It seems almost as though the second card is running at half speed (pci 4x?) and is bottlenecking the other card, but in the mobo manual the slot I've got it in is listed as pci-e 16x. I'm running a fresh install of Windows 7 64bit and here are my system specs:

Asus Z97-AR
i7-4790k @ stock
8gb ram
(2) 270x sapphire
700 watt OCZ

Has anyone had a similar issue with any of this hardware? Can anyone shed any light on what the issue may be given the info I've provided? If I've left anything out let me know and thanks in advance for any help.

 

[roadrash151]

I'm having exact same problem with R9 280's. I'll let you know when I figure it out.

 

[Robertwhyte]

update bios? and 59 fps on valley? i take it you had 8x AA off? because if not thats around what my 970 gets (62fps) so if you were testing on extreme hd and got 59fps those puppies are working!