[Kalim]

For instance,

Single Channel DDR400: PC3200 = 3.2GB/second bandwidth

Dual Channel DDR400: runs @ 6.4GB/second bandwidth

Doubled up, like having DDR800, while not so.

 

[Kalim]

What motherboard is it you have, just to be sure?

Some, mostly the older, don't allow Dual Channel.

 

[Kalim]

If it allows it it'll say so in the mobo manual.
Software won't detect it unless its actually running Dual Channel memory at present.

Yes, if you get the same size, the same density, the same manufacturer and model RAM stick x 2, and install them in as your mobo manual instructs for Dual Channel (sometimes if you have more than 2 slots, it can be a specific arrangement rather than any slot), they will run in Dual Channel mode. :smile: