I have an Asus P2B-F Rev 1.00 (early version), running a 1.0 GHz PIII FCPGA 100 FSB at 1.8v on an Asus S370DL slot 1 adapter.
After reading Andy Hui's article in the FAQ section I confidently ordered a 1.0GHz PIII. Unfortunately, it didn't work and after checking the stepping number on the Intel web site I discovered that I actually had a 1.1 chip. Normally this would be a bonus but according to Andy none of the 1.1's will work. I returned the chip and got a 1.0 chip that is now working great!
I was running a Slot 1 PIII 450 FSB 100. My benchmarks were generally in the 220% to 250% improvement over the 450. A real surprise was the increase in graphics horsepower. Most of the graphics benchmarks increased by 1200%. Of course I'm using an old ATI All-In-Wonder 128. This board does not tolerate overclocking so that's why I stuck to the "hard to find" 100 FSB chip.
I have surplus parts if interested: PIII-450, PIII-1000 Celeron FCPGA 100 FSB (will be RMA'ed Friday 1/25/02), MSI-6905 ver1.1 slotket.