Ok, I've been giving this a lot of thought, and in theory it should work. If I get a Windows 8 machine, and then put a GPU such as an AMD 5350 (nice old card that should be perfect for some Dx7 games etc) would it,
a) be recognised by the OS
b) Work with the OS
c) allow me to install things like DirectX 7 on my Windows 8 Machine?
Note that this would be for a desktop computer with something like a 7750 and either a Haswell K part or an ADM FX 83XX part, SSD + HDD and a large PSU.
I'd expect the larger problem at hand would be to run such old games under Windows 8 at all. But with those that do start properly, sure there are drivers there for the HD5000 -series of cards. If you plan to play some specific games then look around for info on whether people have been able to run then under Windows 8 or not.
I had a machine that used Windows 7 which I upgraded to Windows 8 and all DirectX components were preserved, games still ran etc. My new laptop uses AMD Radeon HD 8xxxM series graphics, which don't seem to support anything before Dx9. It has an Ivy Bridge CPU and IntelHD 4000, but it's always the DirectX version that causes me to be unable to play. The reason I say this is because the windows 7 machine which I upgraded to WIndows 8 used the AMD E-350 Mobile APU (dual core 1.6GHz chip with AMD Radeon HD 6350 or something like that). Given that ran the Dx7 games fine, I feel confident it's a GPU issue.