DXDIAG shows the card as having 3GB available to it. As long as the OS and programs run properly I only worry about having enough RAM, don’t care much about how much is actually being used. If it’s a worry I just add more RAM to the maximum the motherboard supports on 64-bit and 3GB on 32-bit.
https://www.tenforums.com/performance-maintenance/23381-unable-use-all-ram-installed.html