what if asus p8h61-mx motherboard?Depends on your motherboard model. It's going to be different for each board. As for why, that's up to the motherboard manufacturers and the chip set designers.
-Wolf sends
Edit: Typically the best is going to be the Intel Core I7-3770K.
The i7-3770K will work in your motherboard after you update the bios if it isn't already on version 701. You also can't overclock with your H61 motherboard and would require a Z77 motherboard.what if asus p8h61-mx motherboard?