OK - all in all I think I own 9 HD7970 graphic cards. All but 4 are stock reference cards. I have one in my game system, the reason why that is in my PC is because that card was the weakest of the first four that I bought - it did not match the other three. So what that means is I have had a HD7970 in system running at 1050MHz on the core and 1800Mhz on the memory since January. This is seriously the weakest of that first batch, as the other were all able to benchmark on air with stock coolers at 1300MHz. Yes I flashed their BIOS so that I could access the voltage options that most retail BIOS do not allow. But what is important is these were bog standard retail reference cards. I literally bought the cheapest that I could. At the time I did not even know what brand they would be, they were marketed as AMD HD7970. I bought one more after I saw how different the weak card was in performance so that I could do 4 way Crossfire and that card benched 1300MHz single card in line with the three others.
The non reference cards I have came directly from a vendor who wants me to bench their product. So I do not know if they are binned VGA's or not. But the fact that they were shipped directly from the vendors head office suggests that might be a possibility as they did not come from the UK office of that vendor. So I am not even going to use them as a reference point due to not knowing how representative they are of all non reference 7970 cards that can be bought from retailers in the UK.
Cheapest card with a reasonable warranty is the way to go I would suggest. All cards will run 24/7 1000MHz and better I am confident. The reference I have owned all have done over 1200MHz.
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