280X Crossfire - Missing GPU performance

[ToBy_2028]

I have a problem .. 

 

Setup: 

MOBO: ASUS z97 pro 

CPU: 4790k OC 4.4 1.150v. 

RAM: DDR3 2133 

PSU: 860i 

GPU: 2x 280x CF 

Monitor 1: 4K ASUS TN - Main screen

Monitor 2: Crossover 1440p IPS 

 

My 2x 280x only runs at 80-94% Usage: 

 

I have previously run with two CF bridges, for better looks, but yesterday I removeded one of them. Then I got a big performance boost (about 15%) (GPU usage 99% on both), but after testing for an hour, I lost performance again, after closing the benchmark application. 

 

I then noticed that afterburner shows that both GPUs have exactly the same usage, which is new .. They are located at 80-94% usage - I want 99% back along with the good FPS 

 

I've tried 3 different drivers, 3 different GPU bios, a ton of different overclocking setting and a new windows 8.1 installation. 

 

Please help me. I want the amazing perfomance back.

[AlwaysFSX]

Never run two bridges if you have two cards. That murders performance. Revert your BIOS', completely uninstall and then reinstall the driver, and put all overclocks back to stock and see how the performance is.

[ToBy_2028]

Never run two bridges if you have two cards. That murders performance. Revert your BIOS', completely uninstall and then reinstall the driver, and put all overclocks back to stock and see how the performance is.

 

I have tried but without success. 

 

I think it's strange that Afterburner shows that the GPU has the same usage ?? 

Usually GPU2 99% stable usage and GPU1 95-99%

 

Bad CF bridge??

[AlwaysFSX]

 

I have tried but without success. 

 

I think it's strange that Afterburner shows that the GPU has the same usage ?? 

 

Bad CF bridge??

 

I don't think so.. Test each card separately benchmarking them.

[ToBy_2028]

I don't think so.. Test each card separately benchmarking them.

Is it normal that the GPU usage is the same on both cards??

[AlwaysFSX]

Is it normal that the GPU usage is the same on both cards??

Occasionally, yes.

[ToBy_2028]

Occasionally, yes.

But all the time in alle games/benchmarks/apps???

[AlwaysFSX]

But all the time in alle games/benchmarks/apps???

Not really, no.

[ExcitezR]

i run a simalar setup to you and my 280xs dont run at 99% when gaming because thats a limitation of crossfire and SLI it won't scale perfectly. the only thing i would say is overclock them