Correct. I should add a rider on the graph I produced. When a new platform is out, I get locked in to the drivers when it was released. For Ivy Bridge, that was 12.3 for Catalyst. Things may be different in 12.9, but I doubt they would have changed much for Dirt3. If anything newer games would work better!
Yes. I'm the motherboard reviewer. But I'm also on the OCN HWBot overclocking team, and a sub-admin of TeamGB Overclockers.
Here's some more data. Again, Dirt3, 2560x1440, All the special stuff turned on, 7970s, 12.3 drivers, CPUs at stock with 16 GB DDR3-2400 9-11-11(or as close to it).
The boards used:
ASUS Rampage IV Extreme - X79, i7-3960X. x16/x16/x8 and x16/x8/x8/x8, has MultiCore Enhancement
ASUS Rampage IV Formula - X79, i7-3960X. x16/x16/x8 and x16/x8/x8/x8, has MultiCore Enhancement
ASRock X79 Extreme11 - X79, i7-3960X, x16/x16/x16 and x16/x16/x16/x16 (uses two PLX 8747 chips to go x16/x16/x16/x16, but those chips cause 2-4% drop on perf each) in PCIe 3.0 and PCIe 2.0, no MCE
ASUS P8Z77-V Premium, Z77, i7-3770K, x16/x8/x8, x8/x8/x8/x8 all PCIe 3.0, uses a single PLX 8747 chip, has MultiCore Enhancement
ASRock Z77 Extreme9, i7-3770K, x16/x8/x8, x8/x8/x8/x8 all PCIe 3.0, uses a single PLX 8747 chip, no MCE
Gigabyte G1.Sniper 3, i7-3770K, x16/x8/x8, x8/x8/x8/x8 all PCIe 3.0, uses a single PLX 8747 chip, MCE-Plus
EVGA Z77 FTW, i7-3770K, x16/x16/x8, x16/x8/x8/x8 all PCIe 3.0, uses a single PLX 8747 chip (routed differently), no MCE
Gigabyte Z77X-UD5H, x8/x4/x4 all PCIe 3.0, no PLX, MCE
Biostar TZ77XE4, x8/x8/x4, last card is PCIe 2.0 x4 as it is routed through the chipset, no PLX, no MCE
ASRock Z77 Extreme6, x8/x8/x4, last card is PCIe 2.0 x4 as it is routed through the chipset, no PLX, no MCE
(MCE is Multicore Enhancement - read about it http://www.anandtech.com/show/6214/multicore-enhancement-the-debate-about-free-mhz)
For Dirt3, X79 wins out. After that, you want PCIe 3.0 with a PLX, and finally the bottom two have that x4 PCIe 2.0 setup.
For Metro 2033:
It doesn't matter that much, we're all GPU bound. But picking the right board would give 5 FPS difference if you care about it. In this case, X79 or high end Z77 is still the way to go.
Out of my Z77 and X79 reviews, the ASUS X79 ROG boards, and the Gigabyte Sniper/UD5H Z77 boards are the ones I gave awards. I don't give awards out like some websites do with free nachos. Awards my end have to be earned, no-one gets a free ride where I'm concerned, and the manufacturers know that.