Comments about Crucial 4GB kit (2GBx2) Upgrade for a ASUS P5N-D System:

Upgraded to Win 7 64bit which eventually resulted in replacing mobo with an Asus P5N-D & 8Gb of PC6400 from another company which would not run more than 4Gb without freezing Windows right away. RMA'ed that ram (prop's to [...]), purchased 8Gb of the Crucial Ballistix but it wouldn't run either. Beefed up the PSU to 1000w- still no love. Called Crucial's tech support and had a very lengthy and cordial conversation with Luke (I hope he doesn't mind me dropping his name). Together we reasoned that a video conflict might be my problem. Sure enough, swapped out graphics cards with something much newer and immediately all 8Gb of the Crucial Ballistix fired up and has been screemin' ever since.Long story longer... the thing is, Crucial is the only manufacturer I could find that specifically tested their (Performance) ram in my mobo. Their tech support was great and I'm a very satisfied customer and they give you a lot of space to ramble on with your comments!