Some people have had success oc'ing system busses. Im absolutely against it. They are not as stable, and if
it all goes south, so does you mb, and cpu and well, what ever it wants to take with it. I myself got in a little
too deep on the MacMod Server Mod, and toasted the board and cpu. Everything else seemed okay. We learn
from mistakes but your's could be an expensive one and I already had replacement parts waiting. You may want to
look at some cpu upgrades (which use newer cpus, but are still with the fat cache) or go all out and buy a G5.

By the way, I was all for taking mine to 1.5dp, but could not afford the risk and just bought a dpG5 instead. Man was
it worth it.
-maestro

I will admit some trepidation at the thought of overclocking my MDD's bus. However, looking at the specs across the board of MDDs, mine is a second generation with FW800. All the first gen were running a 133MHz bus like mine, all the others run 1.67MHz. It looks to me like my machine is the first example of Apple's tendency to deliberately cripple the base model in every given range of PowerMacs (Think about the G5s with only four RAM slots). So based on this I figure there is a good chance that my board is the same as the other rev2 MDDs, and quite likely, the chip is the same too. Just downclocked by Apple, since they couldn't get the top of the range ones to run any quicker.....

I guess I could check the part numbers on some logic boards.

Any thoughts?

That may very well be. Check you bus controller, the Motorola chip and see what it says. By all means, try it, but be careful and take the time to be causcious. Good luck.
-maestro