I ran some thermal tests on the X2 using a standard retail heat sink. I also ran the same tests on the FX-55 to see if the extra core created much additional heat. The results of the two CPUs were surprisingly the same; they both topped off at about 49C with a 100% load, and went down to about 25-30C at 0% load. So the extra core doesn't produce any extra heat.

The warranty on the new dual core CPUs is the same as on the other Athlon 64s. If they are purchased in a retail box (with Heat sink) AMD offers a 3-year warranty on the CPU. If they are purchased as OEM, then AMD doesn't offer a warranty on it, make sure you know what warranty your retailer offers before you buy it.

So should you buy the new dual core CPUs now? Well it depends on what you need to do with it. The Dual core CPUs Perform much better then the FX-55 on CPU intensive tasks, which would be things like DVD encoding, and Photoshop, however they perform about the same in games. However, dual core is the future, so as programs are written to fully take advantage of the second core you will see dual cores getting much better scores then single core CPUs.