I have moved on from a socket 775 from a 478, I had a thermaltake XP-120 and it cooled my sckt 478 P4 amazingly, i've even think they have a special bracket to transfer it to the 775. Also as another option you could try the Swiftech MCX478-V I have the MCX775-V which is the socket 775 version of the same heatsink. Those are just my suggestions from personal experiance, also they are a bit pricey.