Originally Posted by Frag Maniac
Each one stock the difference is quite a bit more than that, and if you OC a 7950 to 7970 level, it's only just caught up and at or near it's ceiling (depending on model), while the 7970 hasn't even been OCed yet. So let's be clear, the REAL difference is an apples to apples ref comparison, as shown here. http://www.techpowerup.com/reviews/AMD/HD_7950/27.html
As you can see the actual difference is 14% @ 1920x1200.
On performance per dollar, at that time the 7950 only beat the 7970 by 7% bang for buck wise. http://www.techpowerup.com/reviews/AMD/HD_7950/29.html
Fast forward to today though, and with prices like $330 on a 7970 that we're frequently seeing, there's really no longer a better bang for buck value on the 7950 vs the 7970. In fact at the time I made my 7970 purchase decision a few days ago, the cheapest 7950 and 7970 models were both Sapphires, and only 14% difference in price, the exact same as the performance difference. So it was a no-brainer for me, because usually you pay at least some premium for the higher performance, vs a 1:1 ratio.
you did not read my post at all. I mentioned a HD 7950 boost card which boosts upto 925 mhz. this card is faster than the HD 7950 at 800 Mhz which you are talking about. if you max out power option to +20% this card will run at 925 mhz consistently without any clock throttling so even without increasing clocks this card is 3 - 6% slower than HD 7970(925 Mhz) .
I linked the sapphire hd 7950 boost at newegg. these cards with stock voltage of 1.25v are easily hitting 1.1 - 1.15 Ghz at stock voltage. you can see the user reviews are overwhelmingly positive with many running at 1.1 Ghz at stock voltage. At those speeds it matches HD 7970 Ghz.
You can go even further with voltage overclocking. But I agree that overclocking to a certain clockspeed is not guaranteed on any HD 7950 or HD 7970. whats guaranteed is the out of the box speeds. But the HD 7950 boost is unbeatable for price perf even today.