I have just purchased 3 new systems with quad core CPU's. I initially had windows vista installed but found a lot of the betting software i was using wasnt supported by windows vista so i have had to revert back to windows xp. Another interesting observation was that claculations i perform using excel arew much faster on the 2000 version than the xp version. Something to do with multi/single threading i am told. In recent years i have had problems with cpu's being overcooked because of the multitasking i have been taking on. I have now spread the tasks over each system so the speed is enhanced. I run two robots for my betting and since the new systems have been put in place the process is running up to 50% faster.