PCI-E Running at 4x instead of x16

SirConfused

SirConfused

SirConfused

Associate
Joined
3 Feb 2009
Posts
942
So i'm not sure if this is in the right forum or not but after upgrading to a Gigabyte Z87X-OC GPU-Z is reporting that my 670 is capable of the pci-e 3.0 x16 that is stated on the spec sheet but is only running at x4.

Am I going to be losing out on any performance because of this? Is there something i've missed somewhere and accidentally throttled the pci-e slot without realising?

I've done as much reading as I can on this but I can't seem to find an answer on how much bandwith GPU's need to utilise in a single card setup.

Thanks for any light you folks can shed.
 
How are you judging the bandwidth?? Are you reading CPU-Z while the card is running 3D???

Is the card in the nearest PCI X slot ( orange ) to the CPU??

Could the card be seated incorrectly or throttling due to Overheating?? I would reseat the card and reinstall drivers.

The CPU may also be causing the problem due to bent pins in the CPU socket which are limiting the CPU's PCI X controllers access to the GPU. So ultimately you may also have to remove the CPU check the pins and when replacing your heat sink make sure you don't over tighten.

While the CPU is out of the socket do a full system clear too so Battery out for 30mins before rebuilding.
 
I'm judging by using GPU-Z while the gpu is loaded.

The card is in the 2nd slot as it won't fit in the first due to the placement of the pci-e 1x slot and after reading up it looks like I would only get 8x but that's still better than the 4x I'm currently seeing.

I only just fitted the CPU but I fear there may have been some over-tightening so i'll have a look in to that, unfortunately that can't be done until Monday though :(
 
Why do you need the x1 slot? x1 devices can work in x4/x8/x16 slots you know...

It's only the very first slot that does x16. The second slot does x4, the third does x8 (and causes the first slot to drop to x8) and the forth slot does x4. Since you have the card in the 2nd slot, this is why you're seeing x4.
 
Just had a look on the Gigabyte website the 2nd and 4th slots are both labelled as 4x (although they look to be pinned for 8x in the photo).

You'll need to use the 3rd slot for 8x, or as Orcvader says use your 1x card in another slot (4th slot is probably best as it looks like its connected to the southbridge).
 
Last edited:
SirConfused said:
The card is in the 2nd slot as it won't fit in the first due to the placement of the pci-e 1x slot and after reading up it looks like I would only get 8x but that's still better than the 4x I'm currently seeing.
Click to expand...
Do you have a soundcard or somthing in the pci-e 1x slot? That's giving you not enough room to install the GTX 670 in the 1st Orange slot?

Only the first 3 Orange slots can share bandwidth, the last PCI-E slot gets bandwidth from the PCH and only the PCH, so if you do have some sort of PCI-E card other than a graphics card, put it in that slot.
 
One thing to consider is the Haswell and Z87 architecture.
The PCI-e slots are connected to different controllers. Some share the PCI-e lanes controlledy the CPU - these are PCI-e 3.0 and only one can run at x16 if you use any of the other lanes from the CPU it drops the first slot to x8. The other slots, usually x4 and x1 are PCI-e 2.0 and are controlled by the Z87 chip, thus they share a different pool of lanes and bandwidth to the PCI-e 3.0 slots.
You need to check your board specification and use the PCI-e 3.0 x16 slot for the graphics card and one of the PCI-e 2.0 slots for other things like sound cards.
 
Thanks a lot for the feedback guys, I actually ended up re-seating the cpu and pulling the cmos battery out last night anyway just in case. I could have sworn I read that the board was 16/8/4/4x so after yesterday I was expecting 8x from the 2nd slot.

I mostly put in in the 2nd out of convenience as that's how long my tubes were and I wasn't planning on draining my loop at the time and I do have a sound card in the pci 1x.

Looks like I will be draining the loop and shifting stuff around at some point when I get the time.

Thanks again for all the help folks.
 
SirConfused said:
I mostly put in in the 2nd out of convenience as that's how long my tubes were and I wasn't planning on draining my loop at the time and I do have a sound card in the pci 1x.
Click to expand...
Put the soundcard in the 4th (last) orange slot, it should fix the problem, and then you can fit the graphics card in the 1st orange slot running at x16. :)
 
SirConfused said:
Thanks, i'll give that a try as a temporary solution.
Click to expand...
No prob. I was very very close to buying the Gigabyte Z87X-OC, I would have had the same concern as you, so asked on another forum to clarify the way Z87X-OC works.

I was told the 4th orange slot will run any PCI-E card without interferring with the other PCI-E lanes for the graphics cards, due to it sharing bandwith with only the PCH.
Nelly said:
Hey Sin, probally a daft question, but I've got a Creative Sound Blaster ZxR, the 1 x PCI Express x1 slot is right near the first 1 x PCI Express x16 slot, running at x16, if the soundcard is in the last PCI-E 16x slot that runs off the PCH, it won't drop the bandwidth to x8 on the graphics card will it, just making sure I've got that right?

Looking to order a board asap.
Sin0822 said:
You are correct, since the last PCI-E slot gets bandwidth from the PCH and only the PCH you have nothing to worry about because it can't take bandwidth from the other slots. Only the first 3 slots can share bandwidth.
Click to expand...
Click to expand...
Link >> http://www.xtremesystems.org/forums/showthread.php?286318-The-GIGABYTE-Z87X-OC-Review-with-4770K/page2
 
You must log in or register to reply here.
Back
Top Bottom