I haven't tried that exact swap, but I'm pretty darn sure it'll work. Of course, the faster processor is going to run hotter, will that be a problem? I once put a faster cpu into an Acer that (supposedly) wasn't supported by my BIOS, and it worked like a dream. Apparently the critical factor was having to match the bus speed. The T9900 is available in socket P (SLGEE - beware to not buy a SLGKH), so if you find one cheap enough I'd do it.