I looked over at PCOnline images from videocardz and it seems AMD has a weird product stack , isn't HD7750 a HTPC card? Given the pricepoints, I'd say a 2GB HD7790/R7-260X /GTX 650 Ti Boost is where ($150-300 range) GPUs start to get serious (~90% of market) because that's basically what you need for decent framerate med/high 1080p.
Another oddity is how much power the AMD chip is using. Remember higher temps equal more power use, so it could just be a terrible cooler or less area for heat to dissipate (smaller die than GK110).
I really want to know what the power use is under folding@home or Rosetta@Home.
The real question is it a ton of heat produced that isn't dissipated due to less die area than GK110 or just an inadequate cooler / VRM (5+1 on HD7970 yet same VRM is on a R9-290X)? If it's just a terrible cooler and there's no aftermarket cooled cards being made , it'd be a big failure because it'd only be watercooled or put under a Arctic Accelero .
It's limited to 8+6 pin power = 270W-300W TDP ala GTX 480
* PCIE=75W , 6 pin = 75W , 8 pin = 150W
In reality I feel anything over 200W is pretty overkill if it's not furmark (GTX 780 uses up about 220-230W out of box overclocked, ~200-220W for GTX 770, 7970 ~250W , R9-280X uses up to ~300W overclocked)
In Furmark I noticed all reviewers push 300-400W on AMD cards but Nvidia cards 300W for Gk110 and ~200W for GTX 770.Edited by AlphaC - 10/15/13 at 8:15pm