I was looking to buy a second 7950 for my PC but when I went to go buy the second card I found that it has been discontinued. It was a XFX 7950 double D Black edition and I just cannot find another one online. My question is can I just buy a regular 7950 DD or will that negate my performance increase from the Black edition. I know they are binned differently but is that anything to worry about? NE does have the black edition that is not a DD with one fan in the middle, is this OK? Lastly if there are no issues with using slightly different cards can I get a 7970 DD black edition, and what sort of issues would come from that?
You can have any type of 7950 you want, every 7950 has the same chip.
You can get a 7970, but it will lower its clock speed to compensate for the 7950.
Also understand, if you get a faster clocked 7950, you're other 7950 may hinder it by lowering its clock speed. But you can overclock them to match each other.
Also, with gpu memory, the common mistake is 3gb+2gb=5gb of gpu memory. NOT TRUE. If one of your cards has two gigs, that's what the two cards will use, THEY DO NOT COMBINE.
Sorry if that's hard to understand, kinda tired right now.
If you have any more questions, i'll try to answer them.
Thanks for the info. I understand all 7950s have 3gb of memory, will it still use just 3gb if I cross fire? If so, how do the extra frame rates happen?
Yes, if that is so then your 7950 will utilize the other 7950's memory if it has the same.
Crossfire works by a process called AFR. What that means is both cards work on alternate frames, hence 'AFR' - Alternate Frame Rendering. Basically one renders one frame and the other renders another and spits it back out on your screen.