Well, I got a hold of another Barton 2500+ This one is a week 42 (other one was a week 38) and swapped it into my system. Before, Prime would fail after 20 min - 2 hours at 208 FSB & 1.75V. Now running at 210 FSB & 1.65V for a warmup and Prime has been running rock solid for the past 4 1/2 hours. Gonna leave it run overnight and tomorrow we'll see how far this mofo will go. 
NF7-S Rev2
512mb GEIL Ultra Platinum PC3500 CL2 2-3-3-6
Radeon 9800 Pro
LRWW CPU block
DD Maze4 GPU
Thermalright NB-1C northbridge cooler
Water chilled to constant 17*C
NF7-S Rev2
512mb GEIL Ultra Platinum PC3500 CL2 2-3-3-6
Radeon 9800 Pro
LRWW CPU block
DD Maze4 GPU
Thermalright NB-1C northbridge cooler
Water chilled to constant 17*C