Upgrading My PC* | EDIT: Building PC - Help with parts.

[Hitman]

Erm, I heard that if you have 2 different types of ram running at different speeds you'll lose performance on the faster ram or some shit.

yeah, the faster rams run with the same speed as the slower ones.

For example: If you buy  4GB of DDR2-667MHz and 4GB DDR2-800MHz Ram, all 8GB would work with 667MHz.

To prevent that just buy the ram with same speed (DDR2-800; DDR2-1066 etc).