E8400 cant change the FSB at all!

I have a Gigabyte GA-P35-DS3P Mobo, coupled with 4GB of OCZ PC28500 Reaper HPC and a E8400.

I have been managing to overclock in the past, alright I did have a couple of problems when the mobo failed to boot on trialing it but got it running from 3ghz to 3.8ghz without too much hassle on about 1.35v vcore.

Now I have a problem that I cannot change the FSB at all, it allows me to edit it and it says that its done it, but wen i load windows vista (business) and go to my computer or run cpuz it just tells me that it is running at the standard 3ghz.

I have done some research on google and can find NOTHING about this issue from anyone else, does anyone out there with more experience than me have any idea as to why this may be happening?

Any help would be appreciated!

Thanks



Ben