Personally, the first place I start is the FSB.
If you can do a 5 divisor on your FSB, then put that thing to 166 and see if your mainboard can handle it.
You'll have to (obviously) crank down your multiplier to do it. Which means unlocking that XP.
There is a significant difference between 100 and 133. There's a pretty decent difference between 133 and 166, especially when you're doing 4 or 5 things at the same time. Like burning a cd while playing a game.
"I personally think filesystems should be rewritten from scratch every 5 years..." --- Hans Reiser