Forget about this. You can check performance of your CPU at monero mining for example here
http://monerobenchmarks.infoEven modern CPU will not give you such performance as ATI/nVidia. But if you've got a bunch of "useless" servers you can get some background profit by allcoating few of their core for mining. Lowest payout for moner as i know was at dwarfpool - 0.1 XMR.