I have 1.5gb of DDR400 ram installed, why does it show up in bios as DDR333?

Answer 1

Because you either have a messed up BIOS (unlikely), or you have DDR 333 RAM, which means either the package was mismarked (possible), or the person who sold it to you shafted you.

Memory isn't hugely expensive, but the difference in price for DDR 333 and DDR 400 is big enough that selling 333 and saying it's 400 would make enough profit on a few thousand sales to make it a worthwhile crime.

Chuck makes a good point, too. The processor speed may have been misrepresented, also, or you may have RAM that exceeds processor capabilities.

Answer 2

Or your processor is only rated at 333 MHZ FSB.