Memory Upgrades

[obsidian]

Processor: P4 3.0 Northwood
Mobo: Asus P4C800-E

I currently have two sticks of this (512x2=1GB in Dual Channel)

They've dropped a lot in price now (paid $130 for each stick at the time), so I've been considering the idea of getting another two sticks of either the same RAM or different ones depending... I still want my RAM to run in dual channel regardless.

First of all, if I get another two sticks for a total of 4x512, do the two new RAM sticks have to be the same speed and latency as the old ones or can I get faster RAM like PC4000 and faster latency?

Will faster RAM and latency make a difference in performance, or will it just downgrade to the speed of my older RAM?

What do you guys think about the OCZ RAM I posted above... should I still get that or do you have any suggestions for anything better?

Thanks.

[axbaby]

ram will run at the max speed of the slower ram.
latency etc