dogman, is your CPU the E6500 or the E7500? Either way, you have a 266 MHz FSB frequency. The limiting factor is going to be your motherboard. The G41, being an economy chip, has an upper FSB limit of about 350 MHz.
My two cheapy systems:
GA-EP35-DS3P | E7500 OC'd to 4.1 GHz (373 MHz X 11)
GA-G41M-ES2L | E6500 OC'd to 3.66 GHz (333 MHz X 11)
On my G41 board, the FSB will not go higher than 345 MHz.
Snipergod, what you are seeing may be vdroop. Or it may simply be the result of errors in the motherboard power regulator. Vdroop will be more pronounced under load. That's how you can tell.