Patriot have really put a lot of work into their memory products; their line of goodies keeps getting longer and it's good to see another player in the memory market who can actually put out some good modules.
The PC2-6400 modules are designed as a high capacity module kit, designed for users who require a lot of memory for encoding or even running Windows Vista, especially 64-bit versions. AMD's love for low latency memory also means this kit is solid gold for it. As for the Intel side of things, any DDR2 supporting platform will love this kit, but in order to get full use out of it you're going to need Windows XP 64 or Vista 64.
In all, Patriot's PC2-6400 modules really have the goods to be worthy of carrying an overclocking title, and with a 4GB capacity you're not going to run out of resources under Vista like 2GB systems can sometimes do.