PCIE is not backward compatable. Mine is a MSI RS480, it has no over clocking stuff but you can increase the FSB 10% to 220. But I actually run it @ 1000MHZ @ 1.1V using RMClock so it stays cooler and takes 1/2 the power. I have it on 24x7 so it like idles when not in use. The ATI chip set is faster than NF3 and close to NF4 speeds. There are a couple of boards with AGP and PCIE-1X none with PCIE-16x and AGP. Getting good dual channel ram also is imperative. You get another 10-20% extra bandwidth. My RS480/3000+ would be twice as fast as your 1.6 P4. AMD has built in cooling which is what I am using, It runs around 55-60C full speed and drops to 40-45 at idle. Most MB's now has both SATA/PATA interfaces cost 5000-10000 depending if its ATI, NF3, NF4, SLI/DLI etc. Lan would be built in. ATI also has built in graphics running doom at 15fps in the lowest mode

you can almost see everything go by and works great with my slow brain and bad eyes.
P4EE 3733 MHz MSI P4N Diamond nForce4-SLI-Intel Dual DDR2-667 7630 MB/s
P4EE 3733 MHz Dell Dimension XPS i925XE Dual DDR2-533 6920 MB/s
Pentium EE 840 3200 MHz Intel D955XBK i955X Dual DDR2-667 6100 MB/s
Athlon64 3500+ 2200 MHz MSI K8N Neo2 Platinum nForce3-Ultra Dual PC3200 DDR 6030 MB/s
P4 540 3200 MHz Abit IC7-MAX3 i875P Dual PC3200 DDR 5780 MB/s
P4 560 3600 MHz Intel D925XCV i925X Dual DDR2-533 5570 MB/s
P4 560 3600 MHz Foxconn 915A01-P i915P Dual DDR2-533 5420 MB/s
Athlon64FX-51 2200 MHz Asus SK8N nForce3Pro-150 Dual PC3200R DDR 5400 MB/s
P4 520 2800 MHz Soltek SL-PT880E-RL PT880 Dual PC3200 DDR 5370 MB/s
P4 3000 MHz Intel D875PBZ i875P Dual PC3200 DDR 4880 MB/s
Athlon64 1800 MHz MSI RS480M2 (MS-7093) RS480 Dual PC3200 DDR 4623 MB/s