X-Fi has a few things going for it compared to the other Creative cards, and especially the SBLive.

• First, you get EAX 3, 4 and 5 support. These higher EAX versions are relevant for games such as Splinter Cell, Thief: Deadly Shadows, Doom 3, Unreal Tournament 2004 and so on.
• Second, you get better resampling when playing older games. This is useful for pre-2001 titles which still used 22 KHz sound samples or even lower in some cases.
• Third, you get an improved CMSS-3D implementation, which is relevant if you're using headphones. It can provide better sound positioning, especially with regards to elevation.
• Fourth, you get 128 hardware voices vs. just 32 on the SBLive. This can make a difference in titles which support it, providing a richer soundstage.

That said, while your system is period correct, it's not an optimal platform for 2003/2004 heavy hitters like Splinter Cell and Doom 3. They will run, but not at very high resolutions and/or framerates. So your mileage may vary.

I had an Athlon XP 2000+ back in 2003 and 2004, and I upgraded from a Live to a X-Fi back in 2006. I wish I had done it sooner, as the improvement in audio quality was easy to hear even without the better EAX effects in newer (at the time) games. Setting the card to Audio Creation Mode made everything just sound wonderful, and that X-Fi is still in my current Windows XP rig since there's nothing else I can find from that era that has the same blend of game compatibility and sound quality.

I didn't notice much difference going from a Live! to Audigy 2 apart from less bloated driver software
Going from Audigy 2 to X-Fi it felt like a notable improvement in sound if comparing side by side, but on their own even the Live! sounds fine.

This list shows what EAX versions game use, makes sense to at least use a card that supports the latest EAX version needed by a game in your collection

https://www.vogonswiki.com/index.php/List_of_ … ith_EAX_support

If we skip pretty mediocre DOS Sound Blaster emulation, Live is easily replaceable by any other sound card with licensed EAX 2.0 support. Audigy and newer has EAX Advanced HD which was not licensed.

Thanks for the answers. I will look for an X-Fi then.
I'm not too much concerned about performance of this particular build, because if anything runs too slow it will probably run fine on the next PC that I have in storage (a Core 2 Quad), which I may setup one day.