what is the fastest excel machine I can get?

Hi,

I run very large sales spreadsheets with tons of VLOOKUPs and the like. My spreadsheets hit over 100MBs regularly. I was wondering what's the fastest machine I can get to do this stuff?

I know excel does not benefit from dual processor setups. But is that the same of "Duo" or "Dual" single processors? (I'm not sure if that makes sense, but when I see what kind of computers are being sold now, I don't get it either). Is Xeon better than Pentium? Even with different clock speeds?

I hope someone can help me out here! The calc times on my spreadsheets are killing me, and I have done a lot to optimize as well as integrating macros. But no matter how I optimize my sheets (minimizing ranges, etc..), I still have to deal with calcing close to a million cells at a time.

THANKS IN ADVANCE!

-Dale