Not enough information. Processor is important, but motherboard even more so. That AGP slot mainboard could be crap; so could the Intel board. Brand and model number of each mainboard would help us, as cheap boards tend to have a much higher potential for stability issues and/or early failure due to substandard capacitors, funky chipsets with wierd drivers, or other issues due to poorer quality control.
Either CPU is useful for the right tasks, but you want to back it up with a good board. For my wife, I found a micro-ATX i865 chipset MSI mainboard with AGP plus onboard ethernet and sound. It was a new-old-stock Socket 370 board and I stuck a 1.13GHz Tualatin Pentium 3 in it, 512MB of PC133 RAM, and a Radeon 8500LE video card. It does what she needs for a great price, and I still have a reliable board in her system that I know will last.
Intel Q9450 @3.2GHz, Gigabyte GA EP45-UD3P, 4 x 2GB G.Skill @4-4-4-12
Antec P160SW case (modded), Xigmatek 750w PSU
3x 500GB (RAID-5), , OptiArc 7200S, ASUS E818A3T
Creative X-Fi XtremeGamer, Hauppauge HVR-1800, Radeon 4890