Mikhailtech has reviewed 512mb PC3200 DDR400 memory from TwinMOS :
So what can I say, if you need a 512MB piece of the fastest DDR RAM around, TwinMOS’ true PC3200 is the memory for you, just remember, it is not guaranteed to work at DDR400 on any board, just on those that have at least semi-official support for DDR400. The board I used is based on the i845G chipset which doesn’t even have DDR333 support, officially that is, because EPoX added a few extras to their board ;-)
The TwinMOS PC3200 RAM I tested is one of the first true DDR400 512MB modules ever produced, and it not only uses Winbond BH-5 chipsets which are supposed to be the best overclockers, but the SPD timings are very good, though CAS is still 2.5. With a MSRP of under $200, you can’t go wrong with this RAM. Even a 512MB DDR333 CAS2 5-2-2 RAM stick is more expensive.