Intel LOVES socket changes. I suspect this is to maximize their profit by knocking the consumer up for a premium on a new motherboard chipset. Your Q9550 is a socket 775 and is 100% incompatible with an i5 socket 1156 board. Both sockets will dump you in incompatibility-ville with respect to future (significant) CPU upgrades. If the price is right, the 9550 will be a very capable chip for almost every home-use application you can throw at it, including the latest and greatest games not even yet released. You may want to investigate the MB that this PC has you are buying. You probably will want to be able to add a good video card to it in the future. It possibly could be lacking a PCI-E slot which would prevent you from doing that. Also, it should be able to support at least 4GB of memory. DDR2 is what it will have, and you may want to pick some of that up soon since it will likely be hard to find (and expensive) in the not-too-far future.