What happens when you exceed the rated FSB maximum?

I have installed an E8400 3.0 on my P5W DH Deluxe board and after many incidents ( reported on this forum a couple of days ago) I managed to get it stable (AMI BIOS 2901, Saphire 4890 GPU, 4x512 Mushkins, 600 W Enermax PSU), I think because I underclocked the CPU to 2.4 to match the 1066 cap that ASUS specifies for 45 nms processors ( it was not stable at 1333)
My question is: What would be the actual effect of exceeding the 1066 FSB cap , eg, if I increase the CPU speed closer to its rated capacity?

PS- I am considering upgrading my 3 year old motherboard to the P5Q Deluxe to take full advantge of the 8490 GPU

Thanks. So what happens when I exceed the FSB cap of 1066?

So i looked up that mb and as you've probably figured out your motherboard does not support 1333. This is a mb problem, not cpu. So at this point I would overclock the board and see how far you can go, asus is pretty good at overclocking so you should be able to make it work.

First underclock you memory so we don't have to worry about that causing instability. Then slowly increase your fsb until the computer becomes unstable then bring the fsb back down slightly. If at this point you are not up to 1333 you can increase the northbrigde voltage once and repeat the process. Once the northbridge is done you use the memory multiplier to get mem speed as close to 400 as possible without going over.

np

be sure to check all specs before you buy in the future