Faulty PCI-E Lane on MotherBoard?

arexr

Honorable
Apr 8, 2013
3
0
10,510
Hello!
I am new posting to the forum but I think this is where I would post this!

So let me tell you what i'm running:
MSI Z97 Gaming 5 motherboard
Intel i7 4790k
8Gb (2x4Gb) G.Skill Sniper 1866Mhz
EVGA GeForce GTX 970 SC ACX 2.0
Corsair RM 650, 650 watt PSU
kingston SSDNow 120Gb
1Tb WD black


So here is my problem:

For the first 2 or so weeks of having my new motherboard, processor and video card, everything ran fine! Then recently I was noticing crashing to the point where I had to shut my computer off, then turn it back on again when i would play any of the Crysis games. I narrowed it down to the display driver crashing. So i did some reading on the problem and one person suggested I underclock my videocard, After reducing the clock on my video card -114Mhz, the games ran fine with no crashes! For 1 day... Then windows would lock up upon starting the computer. So I re-installed windows and tried again, the crashing still occurred.

Things i've tried:
Replaced PSU
Replaced RAM
replaced the video card with a gtx 660 (crashing still occured)
installed windows on a different harddrive
reset BIOS
Updated BIOS
re-seated videocards


THEN:::::::::::
I moved the GTX 660 I was using as a test card over to a different PCI-E lane... IT WORKED
Same with my GTX 970! The lane they were originally in was a PCI-E x16 lane, I moved them to the x8 lane and they work fine with no crashes!

Both the GTX660 and GTX970 drivers would crash when in the x16 lane, but wouldn't in the x8 lane.

SO:::::
Is my Motherboard expansion slot controller bad? Should i try to return the board to Fry's where I got it from since it is still withing the 30 day return period?
 
Solution
No not necessarily. As you mentioned before, the other two long PIC-E slots that look like PCI-E x16 are really just PCI-E x8. They have the plastic body of a PCI-E x16 port, but you can see the soldered connections only go half way up the port, so it only works as PCI-E x8.

It does kind of give the impression that it might be just the port on the motherboard, but since the PCI-E 3.0 controller inside the CPU is only being used at half capacity, it is still possible that its defective and just can't handle a full load, while running at half capacity it is fine. In truth it kind of seems more likely that it might be the PCI-E 3.0 controller inside of the CPU because of what you did earlier, you reduced the clock speed on your GPU and it...
I would say you might as well do a return while you can just encase it is the motherboard but it could be the CPU also. In the top PCI-E x16 lane (which as you noticed is the only one typically actually running at x16) it uses PCI-E 3.0 standard. While the wire connections themselves are inside the motherboard, the actually controller for this is in the CPU. In fact it connects directly to the CPU and doesn't even connect to the chipset on the motherboard. This is a big help for latency is the reasoning.

While the PCI-E x8 lane you are using now, it could be a PCI-E 3.0 or a PCI-E 2.0. If it is a PCI-E 3.0 port, then its possible the port itself is just bad, but could also be the PCI-E controller on your CPU is defective and when it runs at full load it causes the crash. If it is a PCI-E 2.0 port, both could still be true but the PCI-E 2.0 lanes run from the chipset and not the CPU so they wouldn't be affected at all by this aspect of the CPU.

Just letting you know, so if you do a return on the motherboard and the problem continues, you will know its the CPU that is the culprit and why.
 

arexr

Honorable
Apr 8, 2013
3
0
10,510


All 3 PCI-e lanes on the motherboard are Gen 3. So would than mean that it is the motherboard? Since all 3 lanes run off the cpu and just 1 lane (the x16 lane) has problems.
 
No not necessarily. As you mentioned before, the other two long PIC-E slots that look like PCI-E x16 are really just PCI-E x8. They have the plastic body of a PCI-E x16 port, but you can see the soldered connections only go half way up the port, so it only works as PCI-E x8.

It does kind of give the impression that it might be just the port on the motherboard, but since the PCI-E 3.0 controller inside the CPU is only being used at half capacity, it is still possible that its defective and just can't handle a full load, while running at half capacity it is fine. In truth it kind of seems more likely that it might be the PCI-E 3.0 controller inside of the CPU because of what you did earlier, you reduced the clock speed on your GPU and it stopped having problems for a while. Typically if a port is bad, its cause the physical wire connection is bad, and clock speed has no effect on this. While if it is the PCI-E 3.0 controller inside of the CPU that is slowly failing, under-clocking your GPU would reduce the strain on the controller and would see at least a temporary removal of the problem. Which is what you observed.

I am not saying don't go switch the motherboard, it doesn't cost you anything to switch it out really and if it is just the port then that is great. I am just telling you all this encase you trade it, the same problem continues, then you will know what the problem is and why.
 
Solution

Rart

Reputable
Apr 2, 2015
9
0
4,510
Hi

The problem was the motherboard that was faulty or the CPU (PCI-E controller) ?

I'm having the exact same problem when playing games or benchmarks , but i have a Asus Maximus VII Ranger motherboard .

The video card works fine in the PCI-E x8 slot , info from GPUZ :
(PCI-E 3.0 x16 @ x8 3.0)

But its always crashing the nvidia driver if its in the PCI-E x16 slot , info from GPUZ :
(PCI-E 3.0 x16 @ x16 3.0) .
(PCI-E 3.0 x16 @ x16 2.0)
(PCI-E 3.0 x16 @ x16 1.1)

Intel i7 4790k
Asus Maximus VII Ranger motherboard
8Gb (2x4Gb) G.Skill 1600Mhz RipjawsX series kit
Gigabyte GeForce GTX 960 WindForce 2X OC
Power Corsair CS750M


http://www.tomshardware.co.uk/answers/id-2612156/pciex16-crash-problem-pciex8.html

Thanks
 

garneroutlaw

Reputable
Apr 23, 2015
93
0
4,660
I don't think symptoms are cut and dry for a faulty mobo. I had a similar issue as you did. Swapping the cards to different slots temporarily fixed my problems, but the issue came back a few weeks later. I'm having all types of issues with my cards not running at their full potential as well as an occasional display driver crash. Benchmarks seem to work fine, but playing games is a different story. Swapped CPUs and the problem got WORSE. RMA'd my motherboard tonight. It was an EVGA Z87 Classified.
 

Rart

Reputable
Apr 2, 2015
9
0
4,510
Here works fine in benchmarks and games but just in the second slot .
I was thinking that the problem was windows 7 , but no , i installed ubuntu 14.xx in other hard drive and the problem still happens .
How many time you wait until you get the new motherboard from RMA ?

Keep posting the news about if it works with the new mobo .

Thanks.