Win10 on old hardware?

This another type of story I see intermittently, people try Windows 10 on a 5+ year old machine and are subsequently blown away when it works. By and large this shouldn't surprise anyone. At least, not anyone who follows Windows. Windows 7 marked a shift in strategy. Every version prior to Windows 7 increased hardware specs. Windows 7 actually had lower specs than Vista in many regards. And Windows 8 and 10 don't bump those up. In fact, in some ways effective requirements went down. Meaning, while actual specs didn't drop on paper, memory footprint of the OS and performance were improved in each version. So, as long as drivers work, Windows 7 and even some Vista era hardware should run on Windows 10 and in some cases may even run better.

Windows 7 and beyond is generally where you'll see the best results as Windows 10 should support the same WDDM signed drivers going back that far. Though, some have reported that this isn't always the case.

If you have a much older PC and isn't your sole PC you should give it a shot. Just be aware that it isn't guaranteed that everyone will have the same easy time of upgrading and running Windows 10, either due to a lack of WDDM drivers or the odd case where they don't work despite being WDDM drivers.