I had Kingston memory in 1333 speed, then I had OCZ, all of them had problem. I use my pc for everything, from Business to Gaming, I work in IT so my tasks are quite demanding on the memory, and I multi-task a lot. I purchased 2 of these and now have 8 GB in my pc, running Windows 7 Ultimate 64 bit edition, I can say it has made a world of difference. Kingston memory kept failing, I would get blue screens and Read / Write errors daily. Corsair is excellent, 4 x 2 GB Dual Channel enabled, running them at 1333 Mhz underclocked, with better timings as CAS 9 is a bit low, I have them stable at 1333 MHz with Cas 7 and no over voltage, just stock. Works perfect in hamrony with my Core 2 Quad CPU which is a 1333 Front Side Bus. If I can give any advice here, it is to buy better components, and under clock with better timings, NEVER overclock, you will wind up with junk in no time, and you wont even know which component failed. Hardware manufacturers market the overclocking concept as this is how they make the most money, when you buy new components every few months. With this Memory I was able to achieve better performance for half the price of Cas 7 memory which is 1333. I am very satisfied with my purchase. Amazon delivered quick, and well packaged.