Mushkin PC2-6400 4GB Memory
 

Are you in the market for 4GBs of fast, stable, overclockable memory but
you don't want to break the bank? Well, the Mushkin PC2-6400 (HP2-6400) 4GB
Memory Kit is it! Being able to overclock this memory from its default speed
of 800MHz to 1068MHz is incredible. Especially considering this overclock
was using the fairly tight timing of 5-4-4-12. To be honest, this memory was
a dream to overclock.

http://www.3dgameman.com/content/view/8117/103/