Any Better CPUs for this Dell (something cooler)? ***Edit: found one!

*** See post 18 for info/questions on the new Core 2.

First off, this thing is old, but pretty neat. It is in the boys’ room and they love it. It is still a decent machine, but I would like to look into making it run a little quieter. This machine has the ATI Mobility Radeon 2400 and the Core 2 Duo E6550.

The Computer is a Dell XPS One 20:
http://www.dell.com/support/home/us/en/04/product-support/product/xps-one/manuals

Anybody want to help me look for a better CPU for this guy? Adobe Flash and Minecraft put a decent load on it (40-60% and 60-80% respectively), so not sure if it would take something cooler, more powerful, or both.

Here are some links that may help:
http://www.engadget.com/2007/10/30/dells-xps-one-gets-undressed-and-naughty/
http://electronics360.globalspec.com/article/2231/dell-xps-one-mtg-computer-teardown
https://en.wikipedia.org/wiki/List_of_Intel_Core_2_microprocessors

Appreciate any input on this. If it makes any difference, it is running the latest BIOS, Dell XPS A2010 BIOS 2.0.6, dated March 2009.