I received a Dell 518 for Christmas and I would like to know which after market MOBO I could get for overclocking. I have finished the pin mod on the Q6600 and I am up to 3.0Ghz air cooled but with the locked out BIOS I am at a stand still.
None. Dell cases and motherboards are proprietary. to use an aftermarket board you would need dremel tools to hack up the case, and good luck finding cables to interface the motherboard to the front I/O possilby a new powersupply and of course a retail copy of your OS as you cannot use a Dell disk on anything but a Dell.
Your just better off building your own.
Home Built Sandy Bridge P8P67 i7 2600k @ 4.5 GHz 8gigs GSkill Ripjaws. Corsair 800D Case and AX1200 Ps X-Fi Titanium Fatal1ty pro PCIe Sound Card Dell Studio XPS 1645 Window 10 Pro