Ok I bought 1 stick of a data pc4000. But then I became poor. So I planned on selling it and getting 2 sticks of 256 bh5. I ordered hyperx from newegg... it arrives, and I accidentally ordered the single 512 instead of the dual 256. (I was tired and a price change had moved the single 512 to what the dual 256 had cost the night previously... I looked at the title Hyperx 512 and the price and didn't notice that it was different... anyhow.) Now I've got a single stick of 512 Hyperx.... don't get me wrong it runs 220@ 5-2-2-2.0 with 2.9v (haven't tried any lower voltage). But I had planned on using it on my intel rig, and I went with kingston because it was the best price for 256 sticks bh5... If I had planned on dual 512's I would have gotten buffalo 37 or Black 2 for 20$ less and more respectively. oh well... hopefully my checks will cash, and I'll be able to get another 512 of this stuff soon, (as in before it's no longer available).