Crossfire a 7970 with a 7950 or just get another 7970

[Brock123]

I already have a 7970 (actually just sent it in for rma) and I am looking to crossfire. Searching google to see how it would crossfire with a 7950 gave me a ton of conflicting reports. When crossfiring with a 7950 would the 7970 step down to the same specs? I am sure that if the 7950 had less ram that would affect the 7970 but it looks like there is a possibility that the 7970 can run at it own settings. Also, does anyone know of any bench marks for a 7970+7950 crossfire I couldn't find any? If the 7950 would negatively effect the 7970 then I would just get another 7970 but I would like to save $100 and one 7970 is almost good enough.

Thanks,
Brock

 

[3DVagabond]

Except for RAM amounts the stronger card doesn't step down to the weaker. You, in theory, get performance 1/2 way in between what 2 same cards would have. ie 1/2 way between 2x7970 and 2x7950.

 

[RussianSensation]

AMD cards can work at their own specification (core, memory clocks, voltage and SP/Shaders) in Crossfire. They don't have to downclock or sync'ed, etc.

http://www.overclock.net/t/1220193/...rent-card-of-the-same-series/10#post_16551322

Also from forum member Mazel at OCN:

"In general there's very little information on hybrid 7900 setups. However I do have 7950+7970 setup, and in my opinion you'd be better off grabbing another 7950. The performance is very close once you clock them up to the same speeds, and if you do plan to do a hybrid setup the faster card doesn't down clock. I did some benchmarks comparing the cards if that'll help you."

http://www.overclock.net/t/1196856/official-amd-radeon-hd-7950-7970-7990-owners-thread/15990

Assuming your HD7950 overclocks to the same GPU/memory clocks as an HD7970, the performance hit is going to be 5% for the 7950 card on avg. Since many after-market 7950s already ship with 925mhz GPU clocks, you are nearly there with your 925mhz 7970. Now you'd just need to overclock the memory a bit.

 

[Brock123]

Thanks for the info I am going to go with a 7950 then.