I've got a MCP67M-A2 (7150M) and I've been playing around with it a lot got a vga bios mod on it for 0.86v in 2d from 1.1v and 555Mhz from 425Mhz in 3d and it's limited to 1.2v since anything beyond 1.2v doesn't yield any more overclock. It shouldn't be too hard to figure out which chip will...