If you have the XP2400+ that won't be much of an upgrade but it will let you run the FSB at 166/333 instead of 133/266. Really it's not worth the cost.
The latest A7N8X BIOS does add Sempron support.
If you want an adventure, find out if your XP2400+ is unlocked - it's an older CPU so many are unlocked. If you bought it in 2003 things look good.
Anyway, if it's unlocked you could drop the default multiplier from 15 to maybe 13 and then run the FSB at 166/333. Or even 11 times 200/400.
K8N Neo2, Opteron 180, 2GB G.SKILL PC3200, 9600XT, Cooler Master CM 690/RP-600-PCAR
GA-K8NS Ultra-939, Opteron 175, 1GB PNY Verto PC3500, 9600XT, CM Centurion 5/RS-450-ACLY
A7N8X-E Deluxe, XP-M 2600+ @218x11, 1GB KVR PC3200, 9550, Lian Li midtower/RS-450-ACLY
AN7, XP-M 2800+ @218x11, 1GB HyperX, AIW 9600XT, Antec Super LB/TPII Blue 480http://classicplatforms.com
Keeping "Old Tech" new.