It depends. If you're upgrading to a really powerful graphics card, you definitely want to make sure that your power supply can handle it. If you haven't upgraded any of the major components in a while, it might be time for a system overhaul, too. That usually means a new processor, motherboard, and sometimes RAM, though AMD AM4 motherboards can slot in relatively new CPUs without needing any other new components.  If you're not sure you want to drop that much on new hardware, you can always upgrade the GPU, do some testing in your favorite games, and see if you have the performance increase you want. If not, you can upgrade the other components as needed.