TR Forums

Problem....

My mobo: GA-Z68X-UD3H-B3 v1.0 (bios: F11)
GPU: HIS 6970

The card use to run in 16x mode with the pcie 2.0....now, it only runs in 8x. I have not done anything to the system and all power saving features are turned off.
Any ideas?

Did you recently flash the Bios?

Flashed it a while back, just recently checked the stats for the card.

EDIT: I'll try going back one version in a bit.

EDIT 2: Going to F10 did not help, still 8x. Eh, i'm done for tonight. I also submitted a ticket to Gigabyte.

What slot is your "Recon3D Audio" in? Any other PCIe devices? Z68 doesn't have a whole lot of lanes to burn, so sometimes installing something in a particular slot causes the lane divisions to be reshuffled.

I tried removing the Recon3D and still nothing, BUT, I fixed the issue!

Apparently....USB3 is a throughput hog. In the BIOS, there is a setting called "R_USB30 Turbo". With this Enabled, the highest PCIE speed is 8x, no matter what is installed. With this Disabled, everything ramped back to full speed. I also noticed with this setting Enabled, my BCLK speed was 98.3Mhz, with this setting Disabled, it runs at 100.8Mhz.

The communication to my 6970 is now: CPU > GPU: 5.701GB/s. While before it was 2.343GB/s.

How I knew something was wrong was the amount of stutter in Skyrim seemed to increase without any changes (or new patches), and Borderlands started to do heavier texture popping. I then checked CPU-z and GPU-z and found that they both said 8x link speed. That began the whole investigation. Apparently when I was last messing around in the bios, I enabled it thinking "USB3 turbo? Sure!"

Anyway, if anyone has this setting enabled, check your link speed!

~CC5

EDIT: I hope this helps anyone who is having this problem. There is little to no information on this topic anywhere online that is helpful other than the common "Fixed." post.

On the flipside, your USB 3.0 performance probably isn't doing as well. I'm just guessing, but I'd imagine your motherboard is wiring part or all of your second PCIe 16X slot to the USB 3.0 controller. When in normal mode, it's getting 1X, say, and if you enable that Turbo thing, it gets 8X or 4X lanes. That'll make the USB controller really happy, but it looks like it triggers a lane reorganization, too.

On the balance, I'd imagine more people with Z68 have high end graphics cards than high-throughput USB 3.0 devices, though, so you made the right choice.