Dual Channel RAM questions, please help

For Dual Channel to work, do both my RAM sticks need to be identical, same brand same specs, or can they be different brands, same spec.
E.g. Both PC4200 different brand names.

Thanks!

Fishman is right. However, they do not need to be identical, or even of the same spec. You *can* run ram modules of different specs (i.e. 333mhz and 400mhz), but they will run only as fast as the slowest module.

Matched modules are the best, for compatibility and speed. It also depends on what ram your motherboard supports. Make sure you are using ram that your motherboard supports, for starters.

If you would like to guarantee that dual channel will work for you, implement a solution where the ram modules are identical, and fully supported by your motherboard.