Keep in mind, that putting too new of a video card into such an old system isn't going to help. If you're stuck on AGP, your choices are slim. HD3850/4670 or 7950GT on the nVidia side, all of which are not that easy or cheap to get. If you're on PCIe, it's going to depend on your operating system, what you can get drivers for. If you can run Windows 10 on that, you're going to be limited to 32-bit. I doubt that CPU would even take full advantage of a GT 710. The Athlon 64 doesn't have the features required by 64-bit Windows starting with 8.1. With 32-bit, you're also stuck with 3.5gb of RAM available, so upgrading your memory beyond 4gb, is also going to be useless.