The cpu socket you are using is already 2 generations old so any new processor out today, won't work in your motherboard. Without upgrading your motherboard and ram you are limited to say an I7 3770k but you'll have to find one used as some places still sell them for about $500 on amazon.
The i5-2500k and the i7-3770k are on the same socket.Different socket.
Different socket.
Aren't all vaguely recent chips 'flip chip'?3770K is a fclga1155 CPU
That's not why it requires a BIOS update. It requires a BIOS update because the Z68 was released before the 3770k was a thing. It needs a bios update so the motherboard can recognize the new processors released by Intel that are using the same socket.Technically the Z68X-UD3H-B3 is a LGA 1155 and the 3770K is a fclga1155 CPU, meaning without ensuring the BIOS is F12 or later it will not work.
Can verify, simialrly I have an Ivy Bridge G1620 that didn't POST on my P8P67 Deluxe until swapping out the BIOS chip with the appropriate, supported image.That's not why it requires a BIOS update. It requires a BIOS update because the Z68 was released before the 3770k was a thing. It needs a bios update so the motherboard can recognize the new processors released by Intel that are using the same socket.
It's the exact reason why the Z170 chipset mobos need a bios update to support the upcoming Kaby Lake processors.