Which board? Help me decide.

[OmegaSupreme]

Ok so I have a client wanting to buy one of my rigs and then I'll keep the other one. However, I'm not sure which board I should sell and which to keep since they're both badass boards.

Here's my choices:

AsRock z68 Extreme 4 Gen 3 and the AsRock z77 Extreme 6.

When looking at the boards, there doesn't seem to be a whole helluva lot of difference between the two. Now if I understand it correctly, the "Gen 3" z68 boards added native support for PCIe 3.0, USB 3.0 and SATA 6GB/s.
However, one thing to keep in mind is that I have two unlocked 6950's and for some reason the unlocked BIOS doesn't work on the z77 chipset. This is a known issue that doesn't seem to affect the z68 chipset.

 

[HaX]

your 6950's with unlocked shaders don't work on your z77? that's wierd, have you tried setting it back to stock bios and then reflashing?

 

[Tsumi]

Gen3 only added native support for PCI-E 3.0. Z68 added native support for SATA6. Z77 adds native support for USB 3.0, Z68 does not have native USB 3.0.

 

[OmegaSupreme]

your 6950's with unlocked shaders don't work on your z77? that's wierd, have you tried setting it back to stock bios and then reflashing?

It's a known issue with the unlocked 6950's. Well, only if they're actually flashed to 6970 clocks, which both of mine are. They work if they're not running at 6970 clocks.

Gen3 only added native support for PCI-E 3.0. Z68 added native support for SATA6. Z77 adds native support for USB 3.0, Z68 does not have native USB 3.0.

I could've swore that that particular board had native USB 3.0 too.

 

[Tsumi]

Nope. The Z68 chipset does not have USB 3.0, motherboard manufacturers cannot magically add features to the chipset. USB 3.0 on Z68 was accomplished through external controllers.

 

[apav]

How much of a performance decrease will there be from using a PCI-E 3.0 GPU in a PCI-E 2.0 slot?

I kinda bit the bullet too soon and went for an older Z68 model right before Gen 3 was released.

 

[Tsumi]

First off, PCI-E 3.0 will not work on any board unless you have an IB CPU. Also, you would need a PCI-E 3.0 graphics card in order to take advantage of PCI-E 3.0.

If you do have an IB CPU in a non-gen3 crossfire/SLI motherboard, the primary slot will only work at PCI-E 3.0 x8 with a PCI-E 3.0 graphics card, and PCI-E 2.0 x8 with a 2.0 graphics card. The secondary x16 slot will not work at all. So IB in a non-gen3 board is worse than SB, because the switches aren't made to handle the PCI-E 3.0 signal.

As for performance... absolutely none. The 7970 and GTX 680 are barely held back a tiny bit (~5%) by a PCI-E 2.0 x8 link, and are not held back at all by a 2.0 x16 link.