hell I could be wrong but I'm sure Praetor has it right.
Anyway Astroman it really depends on the proc. and it's FSB (Front Side Bus) when it comes to choosing what type of ram you want. If you plan on overclocking by turning up the FSB then faster ram is a good idea but never higher then what the motherboard is designed for.
Example a proc. with a FSB of 400 then pc 3200 in dual channel is good... A proc. with a FSB of 333 then pc 2700 is good.
Anyone plz correct me if i'm wrong.
PC2100 - 2.1GB/s bandwidth (DDR266 MHz, SDR133MHz),
PC2400 - 2.4GB/s bandwidth (DDR300 MHz, SDR150MHz),
PC2700 - 2.7GB/s bandwidth (DDR333 MHz, SDR166MHz),
PC3000 - 3.0GB/s bandwidth (DDR366 MHz, SDR183MHz),
PC3200 - 3.2GB/s bandwidth (DDR400 MHz, SDR200MHz),
PC3500 - 3.5GB/s bandwidth (DDR433 MHz, SDR217MHz).
http://www.bit-tech.net/review/175/2