Not getting x16 PCI express

maxzuk · 20 Oct 2011 at 19:41

After having huge problems with my new GPU

BSODs
Not OC using Afterburner

Found cause and a good tip on Gigayte mobos or at least mine.

Dont engage Turbo mode on USB3 as it disables x16 on pcie down to x8 now dont ask me why but that was what was causing my problems.

Found that after 2 weeks of googling and good tip to share

Orcvader · 20 Oct 2011 at 19:52

What board do you have? It might be because since the chipset does not natively support USB 3.0 it has to give up some of the PCI-E lanes to help cope with the 3.0 bandwidth requirements. For my board it works fine with no problems. I disabled the Marvell SATA 3 controller as well and the extra lanes was instantly given to the SATA 3 controller, so I have both Turbo mode and x16

.

maxzuk · 20 Oct 2011 at 20:34

Hi

Mobo is a Gigabyte ga-p67a-ud3-b3

How do you disable marvell sata 3 controller as would like turbo on USB3 if possible.

Surveyor · 20 Oct 2011 at 21:00

I don't think it's the Marvell controller that's the problem but Turbo USB 3.0.

Note: Turbo USB 3.0 utilizes 8 PCIe VGA lanes, so it is only possible to enable it with a single graphics card running at PCIe x8 on P67 chipset motherboards, or while using Intel® HD Graphics from the CPU (i.e. no VGA card) on H67 chipset motherboards. It is an option for high bandwidth users.

You can have x16 without Turbo USB 3.0 or x8 with Turbo USB 3.0.

FYI there's only around a 2% reduction in performance running the graphics card at x8 compared to x16.

maxzuk · 20 Oct 2011 at 21:46

Surveyor said:
I don't think it's the Marvell controller that's the problem but Turbo USB 3.0.

You can have x16 without Turbo USB 3.0 or x8 with Turbo USB 3.0.

FYI there's only around a 2% reduction in performance running the graphics card at x8 compared to x16.

I agree but have found for me that that was what was causing my problems with afterburner.

Surveyor · 20 Oct 2011 at 22:03

maxzuk said:
I agree but have found for me that that was what was causing my problems with afterburner.

Running at x8 was causing a problem with Afterburner?

That's odd.

If that is the case then you'll have to turn of Turbo USB 3.0.

maxzuk · 20 Oct 2011 at 22:46

Crazy I know but with USB turbo turned on PCIE dropped to x8 and then afterburner would not save settings, It now saves,boots at startup & profiles actually save.

Will be contacting Gigabyte about Refund on Mobo as it was advertised as a USB3 mobo with pcie16 (NOT ONE OR THE OTHER) Understand that pcie x8 not really much slower but did not spend £350 on gpu not to able to tweak it as cannot run afterburner with usb3 turbo turned on.