Hmm, if your system is saying that it's only 2GBs are you sure that you have 4GBs? Maybe you got ripped off, or maybe some of your RAM went bad. I looked for a specific driver, I couldn't find one. Are you sure it's not an EVGA card? What's the exact model number of it? It should say more of a number like XGF-N640-4GB or something on it.