If your BIOS is locked, you can use the Registry Editor to "spoof" your VRAM amount. This doesn't add power, but it helps games that refuse to launch because they think you don't have enough memory.
If your PC is acting up post-update, try this: gpu vram 512mb download windows 10 upd
You are likely looking for the driver or a specific Driver Update for legacy hardware (common for 512MB cards). If your BIOS is locked, you can use