I see
HERE that the BIOS updated to A03 will support the i5 3450/i7 3770 and 1600 mHz RAM.
Notes from the chat:
A03 =
1. Add the uEFI PXE Lan
2. Updated Microcode to 4.6.0_INTEL_MICROCODE_34 to support IVB CPU
3. Change Intel ME firmware to ME8 8 8.0.4.1441
4. Updated VBIOS to snd_2132_D1.dat
5. No BIOS error message of keyboard by default
Memory =
66GKY 8GB 1600MHz, 512X64, 8, 240, 2RX8
VT8FP 4GB 1600MHz, 256X64, 8, 240, 2RX8
H7JD8 8GB 1333MHz, 1GX64, 8, 240, 2RX8
P382H 4GB 1333MHz, 512X64, 8, 240, 2RX8
1N7HK 2GB 1333MHz, 128X64, 8, 240, 1RX8
G8NT0 2GB 1333MHz, 128X64, 8, 240, 1RX8
CPU =
JJ8D9 Ivy Bridge i7-3770 Quad Core, 3.40GHz, 8MB, 77W, E1
JN8M2 Ivy Bridge i5-3450 Quad Core, 3.10GHz, 6MB, 77W, E1
706FY SandyBridge i7-2600 Quad Core, 3.40GHz, 8MB, D2 (Order for WXGXH)
F6KN0 SandyBridge i5-2320 Quad Core, 3.00GHz, 6MB, 95W, D2 (Order for 828RD)
972H5 SandyBridge i3-2120, 3.30GHz, 3MB, 65W, Q0 (Order for J72KD)
I'm not sure the BIOS would support OC'ing with the 3770k, but the 3770 should be supported with a BIOS update (if you haven't already updated it). The 3770 would be the best that you could put in that setup, but the i5 3450 CPU would be just fine too for 99% of situations.