Who Can Upgrade?
Basically any Socket 423 motherboard equipped with a P4 processor from 1.5 GHz to 2.0 GHz, all of which are still based on the first P4 core (Willamette), is a candidate. For our current project we used a D850 GB desktop board from Intel and installed the latest BIOS on it. Since the board hasn't been manufactured for years now, the "latest" BIOS P18 in this case is correspondingly dated: 11.11.2001.
But this also means you can assume that a BIOS update will make no difference at all except in a very few cases. The Intel board had no problem running the CPU with the desired 2.8 GHz, although it only displayed Pentium 4 in the BIOS - which makes sense since the board doesn't recognize the processor. We assume that most boards will easily work with the upgrade. To be safe, though, it's worth taking a look at the compatibility check on the maker's website.
Rambus vs. DDR-SDRAM