The GT 710 is newer and wouldn't use any of your system ram and should perform slightly better. It has driver support within macOS so the Nvidia driver isn't needed. HD4000 is also natively supported so it's really a toss up which one you use. Most people that use the 710 don't have HD4000 on their CPU. The 710 is simply an easy, cheap way to get working graphics when using a chip like the i5-3470 which has HD2500. If you can use the GT 710 in another system you might as well do that and use the HD4000 in your HP 8300. Do you have at a least 8 GB of ram in your 8300 ?