Hi, I am running on a Compaq Presario CQ50 with Chipset GL40. Current CPU is Celeron 575 (intolerable.) MOBO FSB rating is 667 Mhz, but according to this thread I read that really doesn't matter at all. http://forum.notebookreview.com/threads/gl40-chipset-cpu-compatibility.334009/page-24 Anyways, After doing research, the motherboards manual is here: http://h10032.www1.hp.com/ctg/Manual/c01572022.pdf The socket is PPGA478. I would like to upgrade to a T7800. I am not sure if this works because the above thread doesn't talk about the T7xxx series much for some reason. Please let me know what you think or if any more information is needed.