The most likely problem here is you've set the BIOS without setting the Motherboard ... most boards you'll find a set of 3 or 4 micro-switchs just below the Ram next to the FDD Connector.
Certain combinations of this will give you the FSB you want.
Whoever you've got to make sure the Ram & Processor are BOTH capable of the FSB speed that your setting.
100Mhz SDRAM will be able to use multiples of 50 (50/100/200/300/400)
133mhz SDRAM will be able to use multiples of 66 (66/133/266/333)
DDR/DDR2 Ram and RDRAM however tend to work seperate to this and at given speeds only rather than multiple speeds ... most of these generally won't work on anything other than the given speed they were made for.
PC1800 133
PC2100 233
PC2700 300/333
PC3200 400
so really there are alot of factors which could be causing your system to simply reboot ... but its more than likely the motherboard switchs not set properly.
That said my motherboard doesn't work in 133FSB mode, my AthlonXP is capable of it and my SDRAM is too - but when i set it, just refuses to work.
But then its a cheap Chaintech Via VT8328-686/B motherboard so i've always just figured that the motherboard is bugged.
