I7 950, RampageII Extreme running modest overclock @3.8 ghz. Dual boot system, XP 32 bit and vista 64 bit.
1m time ~10.23 sec, 1 ht off, super pi used 1 thread@ 50%

Out of nowhere, super pi is now using 4 threads, and 1m time is up to 10.7 sec.
Same behavior in XP and vista.

Any ideas???

Haven't changed anything, 1504 bios.