i just purchased the following motherboard/CPU combo... pentium D 820 dual core 2.8ghz 800mhz FSB asus p5vdc-x mobo i also purchased 2 sticks of 512 pc2-5400 667mhz memory... however it's in a separate order and won't be here today with the mobo/cpu. so in order to get my machine running i decided to run to fry's and get some memory to use for the day. they have a 15 day return policy so i could return it if i wish. i went to fry's and they did not have any pc2-5400 so i got a pair of 512 sticks of pc-5400 ddr2 675mhz memory. now i realize that it's not the exact same memory but will these 4 sticks be compatible to run together? i realize they will run at the slower bus speed, but 667 isn't much different than 675. what do you recommend? i'm not really desperate for more than 1 gig of memory, so it's not a requirement that i keep this extra memory. should i get rid of the 667mhz mem and go with this stuff i just got?