Generally sad r9 290x crossfire performance

[Nightfury117]

Hello Everyone,

I have two r9 290x's running in crossfire, I've been getting slightly poor performance in a variety of games but just assumed it was poor optimization, I tried bench marking to check and I only got around 2500 on Unigine Heaven and 3900 on Valley, both cards are slightly overclocked at 1050 mhz core clock and 1300 memory clock, are using the UBER bios and are running x8/x4 pci-e, when looking at log files from gpu-z there are occasional half second gpu load drops from 100 to between 0-15. The drivers are 15.12 omega (most recent).

The specs are as follows

Corsair RM1000 PSU (probably isn't throttling them)
8gb Kingston Hyperx 1333 mhz ram
i7 4790K
Samsung 840 evo 500gb
z97m MSI gaming motherboard
H100i water cooler
Corsair 350D case
Any suggestions as to how to fix this would be appreciated

 

[Brunostako]

It may be because of the PCI-E bus speeds. Usually 16x/8x or 8x/8x is no problem, but 8x/4x could be bad for performance on high end cards.

Have you monitored your GPU clocks and temps? Just to ensure there's no thermal throttle.

 

[Nightfury117]

The temperatures of both cards (especially the lower card) rarely exceed 90 (the cards are designed to run at 95 normally) so I'm not sure if it's thermal throttle, the GPU clocks also seem fairly consistent, how could I be sure that it was/wasn't thermal throttle?

 

[Brunostako]

There are many free monitoring softwares, I think MSI afterburner shows you a group of graphics with the clocks and temps.