Given you say that your graphics card is ageing, could we assume that the PC/main board is also? In which case, your first job is to identify whether your motherboard supports PCI Express, or whether it supports the older AGP only. Then, the physical space available inside your case may be a consideration - some graphics cards are low profile to fit into smaller cases.
What is Amazon Go and will it come to the UK? The store without checkouts or queues