None, it will only benefit extreme ocers who want to be able to run their RAM synchronised with FSB when it is oced to 500Mhz+.
PC8000 is DDR2 1000 so will be able to run 1:1 with 500FSB.
Some mobo offer mem divider which elimiates the need for such RAM, unless of course you want to run it synchronised anyway.
If you are not ocing then anything more than a PC6400 DDR2 800 kit is complete waste, even DDR2 533 will do but given the little price difference it is worth going DDR2 800