Quick Googling turns this up:http://www.hardcoreware.net/reviews/review-195-1.htm
Excerpt: "The issue with a longer pipeline TODAY is the clock speed of Prescott is no higher than that of Northwood, and so we will find that Northwood will perform better clock-for-clock than Prescott in many applications, much the same way Athlons do (although to a much lesser extent, of course)." So much for the performance.
"If the Northwood runs at 60C with a TDP of 82W, what would a 103W CPU make? Well, we've been running the 3.20E at 100% load (running Distributed Folding - join our top 20 team!) for the past 2-3 weeks or so. Using the same retail heatsink, the 3.20E was sizzling away at a consistent 77-80 degrees! And yes, THAT IS CELSIUS.
It should be noted that in all that time, the Prescott didn't produce so much as a hiccup. But if overall case temperatures are a concern, and you have other components that are sensetive to heat, you should probably consider a higher end thermal solution if going with a Prescott. I think we are going to see a whole new wave of mainstream watercooling solutions riding the Prescott core." I'm not sure they put up liquid nitrogen in the 8790. http://www.lostcircuits.com/cpu/prescott/
Excerpt: "The main issues with Prescott appear cache access latencies as well as the longer lead-in times caused by the additional pipeline stages. On the positive side are the reduced manufacturing costs and better scalability with performance. Keep in mind, though, that scalablity goes both ways. Compared to Northwood, Prescott runs rather hot and requires excellent cooling."http://www20.tomshardware.com/cpu/20...escott-30.html
Excerpt: "First, Prescott definitely does not represent monkey business, as it performs at the same level as the Northwood. (...) We should as well put the considerable heat dissipation onto the list, as the Prescott offers no improvement in this increasingly important category. Do you believe buying a Prescott processor is a future-proof investment? You really shouldn't, because that is what Intel wants us to believe, as the real generation and architecture change to socket 775, DDRII memory and PCI Express are few months away yet."
And there's more on the Prescott. Just Google it; this is the tip of the iceberg. And so far, all reviewers said about the same thing. Basically, it's what I said: more heat, no real performance boost, and no real future-proofing (no new architecture like 64-bit or PCI Express).
The 8790 already has the new ATI card that generates heat. It has two hard disks. With the Prescott on top of that, the thermal system must really be impressive. More heat always means less stability and in the long term less durability.