Upping the FSB also stresses other componets as well so your cpu and mobo might not be the limiting factor. Anytime you up that you are risking damaging a component, although its probably a small risk if you have decent components. Really I'd say just keep pushing it if you like then back it off when it starts acting wierd. But I also don't accept responsibility if something fries

I unfortunately don't have good enough heatsink/fan and cooling to really do much with mine (T-Bird 1Ghz), I have upped the FSB some but I have problems when the processor hits about 1.1 and even some random problems below that. I think/hope that since my processor temps dont increase very much (2-3C) when I do that that the problem is because one of my 4-5 PCI cards (depending on what I'm using at the time) doesn't like the faster FSB.