Which RAM to choose?

I have the following motherboard: ASUS A7V266-MX, Chipset type: VIA ProSavageDDR KM266, Max speed bus: 266 MHz. I am using a PC3200 256MB 400MHz RAM memory, but my moth. board says to support max 266 MHz (PC2100, PC1600)...



Now the question is the following:



I want to add a 1GB-Ram memory, but I don't know which to choose between PC3200 and PC2100, cause my computer is using a 3200 (...), but my mother board can't support PC3200 (400 MHz)...Which is the difference between using the 3200 rather than the 2100?



I am not a master, so please correct me if I said something wrong



Thank you all, Happy New Year !

If you've already got PC3200 in there and it's running fine then you should be fine getting whichever costs less, the faster RAM will have been downclocked to PC2100 speeds.

Crucial.com says your motherboards supports a maximum of 2 gigabytes of RAM. 184-pin PC 2100, PC 2700 or PC 3200 are compatible with your motherboard.