From what I can gather is if I have games that are directx 8 or later means no need anything else but use XP OS?

If not there are some early games that supports Directx 8, what about oddball games with directx 9 support that cannot be run on XP for some reason, works best on 98SE? If so, this would means I have to use my P4 with 865 chip set or Athlon cpu with nforce2 motherboard for this?

Thanks and cheers, pentiumspeed.