That is realy m problem, from the reading of the specs and manual I got the impression that it does not have a PCIe 2.0, it is customery for MoBos to have that written quite expliced on specs...
Today and for this system I already had my share of mis-happens, I am reluctant because I already had decide to buy the Asrock P55 Deluxe Mobo which supports i5 and i7 processors with socket 1156, I almost payed for one and in the very last minute I checked again and notice that it does not support i5-760 even though it is a socket 1156 processor that works with a P55 chipset .
After this explained maybe you can all understand my reluctance... does anyone has a system working or ever worked on a Gigabyte GA-P55-UD6-C with a GTX470?
As for the Asrock Mobo I've got quite lost myself, in the supported cpu list for Asrock P55 Deluxe it simply does not appears the i5-760 I am buying... although the rest of the Lynnfield is mentioned...
I thought so too so I send them a ticket but I dont think they will answer it because the newer P55 Mobos (Deluxe3 and Extreme4) are more expensive than the Deluxe, I figure they should have launched a BIOS update by now... it they were going to.
1 x PCI Express x16 slot, running at x16 (PCIEX16_1)
1 x PCI Express x16 slot, running at x8 (PCIEX8_1) (The PCIEX16_1 and PCIEX8_1 slots conform to PCI Express 2.0 standard.)
1 x PCI Express x16 slot, running at x4 (PCIEX4_1)
2 x PCI Express x1 slots
2 x PCI slots
The GTX 470 needs a PCI-E 2.0 x16 and the P55-UD6-C comes with two of those, so u even can install a SLI GTX470 in that mobo.
Regarding the ASRock u can see here the CPU support list for the mobo and support both i5-750 and i7-750S.
Now if u ask me what mobo I'd choose I'd go with the Gigabyte mobo by far.
I had the same answer from MSI with my old K9A2 Platinum and the 955 when comes out, even that I took the risk and buy the CPU without and official support BIOS and after some contact support they confirmed that MSI was working in the BIOS version to support it.