I have a Dual Processor 2,7 GHz. When I bought it it worked, but the temperatures on CPU were quite high, especially under load. Optically there was nothing wrong with LCS... until I've dismantled it. The dreaded white residue on water block - indicating O-Ring failure - and, to my shock, completely clogged pipe (I don't believe the liquid did circulate in the system at all) have left me thinking anybody buying a water-cooled model needs to refurbish the LCS. That said - it's not particularly hard (just a bit time consuming, especially when you're looking for imperial unit size parts in Europe), and the best proof is that I've eventually managed to do it and had no problems since.