Newbie PSU: +12v Question

Hi all, I've been a dweller online here for a time and I've decided to upgrade myself to 'visible' member of the forums. Anywho, I've been upgrading/tearing apart my system (new specs below) and I have a question on power sources. I'm currently running a crappy Austin PSU (450, but untrustworthy & warm) which'll be upgraded shortly BUT, I'm really uncertain what the 4-pin (female)(yellow/black) 12v rail is for. I think it's officially called the atx12v? Is/Was is just an alternative rail? I'm new, but I'm not stupid =) bear with me. Any help would be appreciated

Athlon Xp 3000+
Asus k7n8x Del. MB
1GB TWINX1024-3200LL Corsair RT
2x 180 gig WD HDs, 2x8mb Cache
Radeon 9700 pro
Audigy 2
52x Lite On cdrw
16x dvd
Chieftec case

p.s- I'm picking up the ENERMAX EG465AX-VE (W)FMA. 433W Power supply. <A HREF="http://www.newegg.com/app/ViewProduct.asp?submit=manufactory&catalog=58&manufactory=1400&DEPA=1&sortby=14&order=1" target="_new">Newegg</A> (I read Bum JCRules PSU posts/links beforehand. Thanks JC)

p.p.s- Just out of curiosity, are there any cpu mags you guys follow? I read CPU & Maximum Computing, but I'm hoping there's something better out there.


"Life can move pretty fast sometimes. If you don't stop and look around once in awhile, you might mistake it for an Athlon."