T8700 isn't pin compatible, the best CPU for this would be a T7600 (2.3Ghz Core2Duo)

http://ark.intel.com/products/27257/Intel-Core2-Duo-Processor-T7600-4M-Cache-2_33-GHz-667-MHz-FSB

... as you'll discover they are expensive, I'm using a T7400 (2.16Ghz) in mine which cost considerably less, and a T7200 is a decent upgrade too (2.0Ghz, more cache, is capable of 1080p movie playback).