Anyone else have this pci-e 3.0 @ 8x phenomenon with 290/x card?

I open gpuz and on the bus interface area it says pci-e 3.0 x16 @ x8 i can run the 3d bench thing on it it never goes from x8 to x16 just sticks at x8 has anyone else had this same thing happening?

This happens weather the card is flashed to a 290 or 290x ive tried both just to see if it was a unlock thing.

I'm not even sure this is a hindering of performance i just find it odd to not be using a full pipe.

Mine shows 16 x 2.0 when rendering, perhaps the slot is bad?

Is that while the GPU is loaded or idle?

Looks like he said he ran the 3d test and it didn't budge... that said, check in your bios and see if you can force the slot to PCIe3.0 off auto (default) and see if that helps...I have a 290x, but a different mobo, and it shows 3.0 when ramped up.

shadowdr said:

Mine shows 16 x 2.0 when rendering, perhaps the slot is bad?

Click to expand...

Its supposed to... you have a 2.0 board/slot.

EarthDog said:

Looks like he said he ran the 3d test and it didn't budge... that said, check in your bios and see if you can force the slot to PCIe3.0 off auto (default) and see if that helps...I have a 290x, but a different mobo, and it shows 3.0 when ramped up.

Its supposed to... you have a 2.0 board/slot.

Click to expand...

Yeah,,I meant maybe his slot was bad as mine is at 16x

shadowdr said:

Yeah,,I meant maybe his slot was bad as mine is at 16x

Click to expand...

As far as throughput is concerned a 2.0x16 slot is the exact same as a 3.0x8 slot.

ATMINSIDE said:

As far as throughput is concerned a 2.0x16 slot is the exact same as a 3.0x8 slot.

Click to expand...

Not sure how that is relevant, I think he was just saying the slot went from 8x to 16x as expected when going from 2D to 3D mode for him, unlike OP.

Badbonji said:

Not sure how that is relevant, I think he was just saying the slot went from 8x to 16x as expected when going from 2D to 3D mode for him, unlike OP.

Click to expand...

No, he's saying that his 2.0x16 slot runs x16, but the OP running 3.0x8 is the same throughput as the 2.0x16 slot.

It could simply be that the card doesn't need the full bus so it doesn't utilize it all.

Yes this is in a Asrock z77 OC formula.

i forced the slot to 3.0 like said above one of the first things i tried.

I may downclock this processor and see if perhaps its messing up the lane but im doubtful.

very odd indeed i do wonder if this is a common issue with the 290/x's tho because of the powerplay stuff that goes on with them.

will keep you posted

So I tried to down clock the cpu to 4.5 today and every time i rebooted to windows it was still sitting at 4.6ghz and pci-e still stuck at x8.

So I turned everything off - pulled the GPU / sound card and Battery Let the pc sit for awhile and used the rear cmos reset button.

re-installed the hw started it up and the GPU is @ PCI-E 3.0 x16.

I've heard about some people having problems with these 290/x's after black screen issues not fixing until physical removal of card and I wonder if this is part of that issue or just a mobo bios that was stuck in a failing config.

Either way if anyone has a similar issue try my steps in this post and see if it fixes it for you.

ATMINSIDE said:

No, he's saying that his 2.0x16 slot runs x16, but the OP running 3.0x8 is the same throughput as the 2.0x16 slot.

It could simply be that the card doesn't need the full bus so it doesn't utilize it all.

Click to expand...

Regardless of using the bandwidth or not, if the slot supports x16 (taking into account hardware configurations such as other slots being used, support by CPU etc) it should be enabled under 3D - my HTPC with a HD5450 will show PCI-e 2.0 running at the full x16 in 3D, even though it probably doesn't use enough bandwidth for x4 let alone x8.

Anyway, glad you fixed your problem OP.