Depends. SONY VAIO computers usually have real motherboards with Sony BIOS's on them, which can be flashed with the generic BIOS. (Sony usually uses ASUS motherboards if I remember)
Beyond that, unless there is options to change frequencies, you would have to get a hacked BIOS off the web for your specific motherboard, but I don;t recommend doing that if you don't know exactly what you are doing, and are willing to junk your motherboard if it fails.
I haven't owned an OEM.... ever, except for my laptop, which I modified anyways.

I take that back, my 8088, 286, 386 and my 486 were all OEM's, but that doesn't count. Oh, my Apple][e was OEM also. :P