Sys info showing 2gb instead of 4.

I have OSX 10.5.4 on a Gigabyte ds3l. The 2x2gb ram are GSkill f2-6400cl5d-4gbpq.

Is it really working on a 2gb ? How can I be sure ?

Forgot to mention.. I have one module in DDRII 1 slot and one in DDRII 3 slot. Dual channel config.


Is it normal to have 2gb recongnized ?