Just so you know, here is the latest info:
Their press release has said that sometime toward the end of the month(probably on the 20th), AMD will be shipping thoroughbreds to its customers... This just means that chip samples will be sent out to motherboard manufacturers.
Consumer products come a minimum of 8-10 weeks later, but during that period there will of course be extensive leaks, and towards the end there will be review samples sent out.
Very little about the Thoroughbred is known, and that is because the only current samples are deep within AMD labs, behind volumes of non-disclosure agreements.
Right now, the XP2100 core produces the most heat(about 70 watts) of the whole line, tying with the Thunderbird 1400 for hottest chip ever. If your heatsink slips off one of these babies, I give it a third of a second before it bursts into flame.
The Thoroughbred core will be a MUCH better overclocker, and produce MUCH less heat. In comparison, the P4 northwood core 1.6a chips can run on generic crap cooling up to 2300+ mhz easily.
Next: When chips x86 chips diverged(at the athlon XP and P4), the P4 did about 25% less performance per Mhz in return for less heat, while the XP did 9% more performance and less heat(but not as great a heat reduction as the P4)
The Northwood, the first of the next gen of chips, is smaller, same performance as the P4, and produces much less heat.
The thoroughbred will be 55% the size of the northwood, and produce MUCH less heat, while at the same time doing MUCH better performance, presumably about the same performance per Mhz as the XP.
Wait for the thoroughbred, it will be more than worth it. The best bang for the buck will probably be getting the retroactively cored chips(for example the P4 Northwood 1.6a) that performs at xp1800 levels by default. You will be able to overclock this up to xp2500 levels, which work as fast as a 3200mhz P4. I saw a spec from a motherboard manufacturer that said that the first chips will work at XP1800, XP2100, and XP2200 speeds.