Athlon XP 2200,2400&2600 won't power on;2800 does power on

I have an odd issue with an MSI 7061 KM3M-V. I have three Athlon XP CPUs: a 2200+, 2400+ and 2600+ and the MSI board I am using them in will not even power on. The power supply and CPU fans spin for a moment and stop. I have to turn off the PS switch or unplug it for it to even have a reaction to the front power switch and it does the same thing. I put in a 2800+ and it not only powers on, but boots to linux or windows flawlessly; no blue screens in windows.

The power supply is a coolmaster RP550PCAR 550W with dual 12V rails of 16A each. When I can get into the BIOS with one of the working cpus the 12V supply shows a little low at 11.6V, but that's within 5% low so it's likely ok. It also powers on and works with a two different 1800+ cpus. Memory sticks are 2x1GB DDR Crucial brand and since the system works ok with the 2800 I'm guessing they're not the issue.

Also, I have changed the bus speed jumpers on the board and there is no change.

Mainboard is kinda old; I think I got it in 2004-5, but it has always been flawless I only recently retired it for a core2duo to play more modern games. I just want to build a low end system to give to someone or maybe a cheapo linux box.

I'm at a loss for why it can take a 2800+, but not three chips that are lower speed and lower PS needs. Anyone have a clue?

for real man