that the PC 3200 [DDR400] will run fine. HOWEVER, with the mix it will only run at the same speed as the other stick. Your memory bus is running at 166 MHz [333 when double clocked].
IF your mobo supports the 400 MHz memory bus speed [actually it's shown as 200, the DDR doubles it] and you use only the PC3200 stick, it should run at the full 200/400 speed.
Get the PC3200, that way if you upgrade you while have the faster memory for the new machine [although the new machine would likely use DDR2 LOL]
The only other possibility, which is not too likely, is that the mobo limits the memory capacity that a stick can have in a given memory slot. There was a time when they couldn't take more than 256 MB sticks.
Some would take 512s in the first two slots, but only 256 in the third slot. Varied widely for a while.
Sorry thats a pun...my query is about memory, i currently have 1 stick of memory in my machine - Kingston 256mb 333Mhz DDR PC2700 - What i'm confused about is the 333mhz and the PC2700 parts, i'm looking for more memory but i'm not sure if i need to buy the same i.e PC2700 and 333mhz, can i mix and match? for instance the one i'm looking at is 512mb 400Mhz PC3200, will this have any effect.
Rnning: P4 2.4Gb and XP Pro.