I have 2x512Mb DDR400 sticks of Patriot. I have a motherboard that can suport DDR 400 and my sticks are DDR 400, But its always at DDR 333. When i change it to DDR 400, it crashes. Anyone who had this problem and knows how to fix it, or who knows how to fix it, please help me out

the closest problem I've ever had was that my mobo set my memspeed @ 333 when they should be 400, solution: in the BIOS I changed the memory speed from AUTO to 400 and voila!

I really don't know why it crashes on your pc : p, I doubt it's a voltage thing or a thermal one

it would really help if you told us what motherboard you're using... brand, model, revision, etc.

I'm betting P4P800