I would sell the 2 gb set and just use the 8 gb of pc5300, even if it's a little slower. The 5300 ram has faster timings, so you won't notice that much difference, since you'll have 4 times as much ram. Be sure the board will recognize all the ram; many ddr2 boards have a limit of 2 gb per ram slot, so check your specs carefully before you give him anything for the ram. As long as it's non-ecc desktop ram, it should run fine; just don't mix it with your old ram.