upgrading my gpu

im looking to upgrade my gpu but my motherboard only has a 50 watt gpu slot (although I am using a 60 watt gtx 750 ti in it, can anyone explain why that is working) and I want to upgrade to a gtx 1650 so i am planning to buy a new motherboard. I am using 8gb of ddr3 ram, and an i5 3470. Will...