Will 533 memory work with 800?

I know my motherboard will accept both speeds of ddr2 but im not sure if they will work together, Iv recently put together a new computer and have realised that in order to overclock i would need faster memory than i have bought
(533) . i wish to buy a gig of 800 atm and run it alongside the slower memory , is this possible?

I dont have enough for 2gig atm. thanks


Motherboard is gigabyte 965ps3

Yes, but they will run at the speed of the slowest rated chips.