Gigabyte M55S-S3 RAM problem

[evo85210]

Currently i have a 2Gb RAM installed on my M55S-S3 MB
and i found two old 2 512mb DDRII 533 ram in my drawer, and i thought i'd add more ram, but then i can't?

when the 512 RAM is installed along side the 2GB ram, the PC will boot to the Gigabyte boot screen and hang there
when only the 512 RAM is installed, there is no screen and the PC keeps beeping
if i only installed the 2GB RAM, it boots fine

is this an incompatible issue? or is the 512 RAM dead?
attached is the photo of the 512 RAM

[themctipers]

Try the other ram.

[SPAS-ID]

You must have Identical RAM to run

[evo85210]

Try the other ram.

sad thing is, i don't have other ram, i think the 512 ram works on another desktop, i'd have to pull out the other desktop from storage to confirm

 

You must have Identical RAM to run

but even when i only install the 512 ram, it still doesn't work?