So i've been putting together a machine for Windows XP. I just have a few questions on the video and sound card options

for video right now I have a PCIe Geforce 9800GTX+ OC 1gb card. this thing was a monster for its day and its actually only recently I replaced it with a GTX 960. I'm trying to pretty much cover as much as the XP era as possible so early 2002ish to maybe 2008 or so with this machine so compatibility is a high priority followed by speed. so 9800 to fast? to slow? any particular drivers I should be using?

for the sound card I'm using a PCI SB X-Fi. I don't recall the model off the top of my head but it has its own RAM i think. Is there any advantage to using a PCIe sound card?