Just built a new machine:
ASUS P8P67 PRO MB
8 GB Corsair Vengence RAM
XFX XPS-850W Power Supply
HAF 922 Case
2 X Galaxy GTX 470 1280MB Video Cards
Scythe Mugen CPU cooler
2 X Samsung F4 1TB HD
1 X ASUS DVD-RW drive
Windows 7 64 Bit Home Premium
I hooked it all up, loaded the OS, and it booted first time.
Then I OC'd the processor to 4.5GHz and it's stable as a rock.
Then I went to play with the VCs, went into the Nvidia control panel, and there is no option to turn on SLI. I have the SLI bridge in place between the two cards. They are in the two x16 slots. Both cards show up in Windows Device Manager and in the NVidia control panel.
I saw one thread that said to roll back the Realtek LAN driver. I looked in my device manager list, and it says the driver for the Gigabit LAN is Intel version 220.127.116.11, dated 9/21/2010. So I can't roll back the Realtek driver because it doesn't have one.
I hope someone out there has some other ideas I can try. I have not yet done any of the following because the rest of the computer is running great:
1. Update motherboard BIOS
2. Update VC BIOS
3. Update any drivers
I did try to reinstall the Nvidia drivers with the latest version - no joy.
By SLI bridge, I mean the connector between the two cards. And yes, there was only one that came with the motherboard. Should I have more than one?
The instructions for my GTX 465s said to use both sli connectors in 2 way sli, I would assume the 470 is the same. I never tried with just one bridge so I'm not totally sure that is your problem, hopefully someone else can confirm for you before you go out and order another SLI bridge.
Right after I wrote this, my internet died. So I had two problems to attack. I fixed the internet problem, then I downloaded the very latest drivers Nvidia had to offer. Once they were installed, the SLI option showed up! I turned on SLI and played around a little, and all I can say is WOW! The performance is amazing, especially compared to my poor old ATI Radeon 3650 HD card. Now to OC the 470s to squeeze just a little more performance out of my system...