ByDesign - Did you do what Shamus and I told you?
Just try the RAM in different slots and see if it works. Try these combo's in slot 1,2,3 respectively and check the results with CPUz:
-What you have now 256, 256, 512
-256, 256, nothing
-Just the 512 in slot 1
-512, 256, 256
Then look at the results you recorded from CPUz and use the best combination.
Vanquished:
CPUz.exe is a small, free utility (
www.majorgeeks.com) that shows you all kinds of technical details about your CPU, MB, RAM, etc. The best I have found.
How your MB responds to 3 sticks of ram depends on the chipset and the Bios. ASUS offers the most capability for using bizarre combinations.
If you have 4 slots you could do 2x512 and 2x256 to get full performance and capacity. READ the manual all kinds of boards have all different kinds of restrictions on RAM usage. Download cpuz and try different arrangements of the 3 sticks you have and see which gives best speed and daul channel support.