OT: Help buying a new computer

[Thermodyne]

Will said:
Memory types can be a bit confusing at times... especially because some sellers screw it up. "PC400" probably means "DDR 400MHz" since it says it's dual channel, which is the same as "PC3200".

WTF:P......You want to splain that to me.

Dual channel means two memory channels as opposed to one for the old DDR standard. (Almost twice the bandwidth)
For DDR
PC2700 = 333MHz
PC3200 = 400MHz
Top end sticks are now
PC4800 = 600MHz
Top end DDR2 sticks are
PC6400 = 800MHz

If you are not going to OC, just get 2 sticks of the fasted standard that the board supports. It takes 2 sticks to make use of dual channel.