Originally Posted by JonathanM
The 6600 is faster and has 4MB of cache. However I doubt it's as overclockable as the lower clocked CPU's.
Wrong. I have had both an E6400 and my E6600 now and they both OC similar, E6600 being the slight favorite.
E6600 is easier because of the higher multi, also meaning you can save a little bit of $ on RAM.
Stay away, however, from the E4300 and E6300 as native Allendale cores (e4300) have begun showing up in the E6300s. (week Q640) http://hardforum.com/showthread.php?t=1138241
Anyway, I would only get an E6600 if you encode video/audio alot. In every other application, you will not notice the extra cache..