I'm building a PC with pcpartpicker.com I found a Intel Core i5-3350P Ivy Bridge and at $179, I can't pass it up. However, the best MOBO I can find that fits my budget is an ASUS P8H61-M LX3. It says UEFI BIOS does that mean I don't have to do something with the MOBO to make it compatible? If not, how do I upgrade/"flash" the BIOS? Will I need another CPU? I have a REALLY old CPU around here somewhere, will I need that? Thanks.
unless you can confirm that board comes with the near latest BIOS that supports Ivy Bridge CPU's out of the box, you will likely need a BIOS update. to do that, you need a Sandy Bridge CPU. no random old CPU will work with it.
even with R2.0 version of that board, you'll need BIOS 0402. the earliest BIOS it MAY be packed with will be ) 0304.
i suggest simply going for a B75 board from Asrock/Asus/Gigabyte for a few dollars more. less hassle and more likely to be compatible with that 3350P.