Prime 95 question, part 2

I've cooled down my Athlon XP 2600+ as much as humanly possible. I reseated it with good thermal compound and a brand new, all-copper heat sink. I'm running about 52 C at idle and about 10 degrees cooler on Prime 95. My computer still reboots when I run the "small fft" test. Does failure of this test specifically point to the CPU? My chip is still under warranty. Does this test reliably point to a bad CPU? If not, is there a way to test only the CPU to see if it is bad or not (perhaps another freeware program)?

I've tested my ram, gotten a new power supply, etc. Everything checks out fine, so I'm down to either the CPU or the motherboard as culprits. Any info would be great.