HD 7850 CrossFireX Question

[DiamondFX]

Hi, my system configuration is as follows: 

 

CPU: i7-3820 4.3GHz, 

MB: ASUS P9X79, 

GPU: 2GB XFX HD 7850 & 2GB Sapphire 2GB HD 7850 (CrossFireX), 

RAM: Corsair 16GB 1600MHz CL10, 

SSD: 120+120GB Kingston V+200 Raid-0, 

HDD: Seagate Barracuda 2TB, 

CHASSIS: CoolerMaster HAF 912 Advance, 

PSU: CoolerMaster 750W CX 80 Plus, 

COOLER: ThermalTake Contact30

 

I am currently using the 13.8 beta drivers since it has solved some of the frame-pacing issues. When I check the GPU-Z, the bottom card (the Sapphire one) is always at full-load running at 920MHz and 1250MHz memory clock even when the computer is on idle. When I play games, they both increase, which is normal. When I disable the CrossFire, they both drop to stock, 300MHz and 150MHz. Is this some kind of an anomaly or are these cards designed to run this way under Crossfire?

 

According to my gaming benchmarks I believe I have 50/70% FPS increase so I am happy with the set-up but this thing bothers me. Are there anyone who has experienced something liked this or have a similar Crossfire set-up? Any help is appreciated.

 

Thanks in advance.

 

 

 

 

[Excon]

I've seen this issue alot recently with running CF on the new drivers. I think its a bug and will get fixed hopefully in the full release of 13.8.

[xAcid9]

Try disabling ULPS via MSI Afterburner.

[Levent]

also this might be related to the game because integrated application profiles disable crossfire on few selected games but i havent seen that issue since i disabled ULPS

[beefalo]

I've seen this issue alot recently with running CF on the new drivers. I think its a bug and will get fixed hopefully in the full release of 13.8.

This is an issue with the new drivers. The clock and usage monitoring is messed up. My 2nd 7970 always shows 99% usage in games even when the first one is at 50%. My performance is fine so I just don't worry about it. Maybe afterburner will update to fix it soon.

[DiamondFX]

The other issue I might need to fix is this: The Sapphire card is factory overclocked to 920MHz core clock and 1250MHz on the memory, the XFX is stock at 860MHz and 1200MHz. Since I am using the Crossfire, would be a good idea to down-clock the Sapphire card to speed of the XFX card or should I OC the XFX card to the speed of Sapphire? I don't want to down-lock Sapphire because its VDDC is 1.210 avg and the XFX one is  1.010 avg. Any thoughts on this? 

BTW, before the Crossfire, I only had the XFX card and it handled the 950MHz core clock and 1300MHz memory clock pretty good. 

 

Thanks again. 

[Levent]

The other issue I might need to fix is this: The Sapphire card is factory overclocked to 920MHz core clock and 1250MHz on the memory, the XFX is stock at 860MHz and 1200MHz. Since I am using the Crossfire, would be a good idea to down-clock the Sapphire card to speed of the XFX card or should I OC the XFX card to the speed of Sapphire? I don't want to down-lock Sapphire because its VDDC is 1.210 avg and the XFX one is  1.010 avg. Any thoughts on this? 

BTW, before the Crossfire, I only had the XFX card and it handled the 950MHz core clock and 1300MHz memory clock pretty good. 

 

Thanks again. 

i would say overclock both to 950mhz and keep memory clock on 1200mhz 

the sapphire card on my system does 1300mhz core when its the only card plugged it and 1100max when crossfiring with msi card

[DiamondFX]

i would say overclock both to 950mhz and keep memory clock on 1200mhz 

the sapphire card on my system does 1300mhz core when its the only card plugged it and 1100max when crossfiring with msi card

 

Thanks. Let me try. 

[beefalo]

Thanks. Let me try.

One of my 7970s is factory over clocked and the other isn't. I run them at the higher ones stock clocks. Works fine. I could go higher on both if I really wanted to.