To make 100% sure open you case and search for a name on the mainboard. Make sure you also search for the correct revision. (It often happens that from rev. 1.0 to a later version the ram type changes )
In the manual of the mainboard you can find that info.
I have also tried that tool r2baz provided and it worked for me!
nice tool btw
But to make 100% sure i would search for some documentation material of your mainboard.