|"Anyway the processor I need to burn is old , I read that old processors don't have these defences ."|
If that 650MHz processor is a Pentium III or Celeron, you're out of luck. Yeah, even the old P3 CPUs had thermal protection.
Super PIII | Unlocked ES Tualatin @ 1.8GHz (150x12, 1.65v, 512K L2)
2GB PC2700 | 500GB | Radeon x1950Pro | Apollo Pro 266T | Win 7 Pro