Fussy GPU Doesn't Like DP Cable

[talksr]

This really is a new one on me, just wondering if anyone else has had this.

 

HP Z4G4 - a powerful system, complete with an i9 processor and 32gb of RAM.

One Nvidia Quadro P2200 with two monitors. One connected from the system to the first monitor with DP cable, then mini dp to DP on second monitor.

This type of system has no on board graphics, so you have to have something on the PCIe port.

 

The system has been causing the user repeated issues whereby Windows fails to boot and goes into recovery mode. If you use DISM to remove the Nvidia drivers, it solves the issue but as soon as Windows Update installs the graphics driver again, same issue.

The reason we know it is GPU related is before the Windows recovery situation, the GPU shows as having a driver error on Dev Man. As soon as you try and update, as it installs, the system cuts off, reboots and goes into recovery.

 

What has been done....

Replacement Nvidia Quadro P2200 - same issue

Replacement SSD and version of Windows 11 - same issue

OS Restore image supplied from HP to put on specific version of Windows 10 for this system - same issue

Special Nvidia Drivers from HP for this particular MB GPU combination - same problem again.

Different GPU plugged into computer - fixed the issue for a day, then same problem again.

Tried Windows 10 rather than 11, no change there.

 

Next option on the list....replacement motherboard.

I brought the computer into my office, totally wiped the SSD (this had been done multiple times before but didn't help).

It worked fine. Plugged in a second montor still fine.

Ran some CPU and GPU intensive software on it. No issues again.

Fully updated the system, ensuring the GPU drivers were all up to date. Still no problems.

Ran an extensive HP hardware test - no issues reported.

 

Returned the system to the room in question, it worked for long enough to install Windows 11 and again, went to recovery mode.

It HAS to be something in the room.

Tried connecting directly to monitor 2... no help.

Tried using a DP to HDMI converter and then HDMI into monitor 1 and then 2, no good either.

Tried a shorter DP to DP lead into monitor 1....................... IT WORKED.

 

Has anyone had this issue before? I cannot believe all it was, was a cable. The issue is that replacement computers have been plugged into this cable and had NO issues. So the cable does not appear to be faulty.

I am assuming, the issue here is the GPU and cable length combination. The second GPU that was used to try and fix the issue was also an Nvidia. I am assuming these Nvidia cards must struggle if your DP is slightly longer than usual?

The desk is a sit stand so has either a 3 or 5m DP cable.

 

I cannot tell you how much time has been wasted on this so would be keen to hear if anyone else has encounered a similar plight.

:mad: :mad: gahhhhhhhhh!

[IRL]

Have you checked that your DP cable doesn't have the 20th power pin connected? It can cause weird issues like that.

[Oaktech]

We've had issues with DP cable versions - never trashing the connected PC, but just not working or causing display issues.

 

For us the issue has been length of cable - a 10m cable wouldn't work, but an 8m would.

 

or

 

Version - the machine and the display were expecting version 1.4 and the cable was not 1.4 compliant - failed to connect or had artefacts on screen.

 

We've also had to use a display port EDID emulator to sort compatibility issues between some our newest DP 2.0 screens and our DP 1.4 or 1.2 devices.

[psydii]

I've not had quite that experience but digital video output running at 5Gb/s+ is very sensitive to the cable and connector quality. If it doesn't carry the USBIF (usb-c) or VESA (DP) branding, it may well not work at longer (1.5m+) distances. Cables that are reliable in mass production are expensive. We don't have much to do with DisplayPort, but for our 10m HDMI runs, the *only* 100% reliable cable is the BlueStream (other cables will often work fine... mostly. But not always. Not everyday. And not with every laptop)

 

Having had to cough for Bluestream, I can see why the only people who can charge enough to make a a reliable 2m USB4 cable are Apple.

 

The amount we've spent on cables over the last few years to get reliability is very close to the cost of a proper HDMI cable testing rig - a tool Linus of LTT (momentarily) balked at the cost of.

 

I've also had a chat with the DP public support team at VESA, and the really short version is: buy a certified cable that runs at the speed of the fastest device connected. The end points will then negotiate a working resolution/refresh rate. The greater the bandwidth required the lower the chance of the two devices successfully negotiating at longer distances.

[talksr]

Thanks guys, I will check the original cable but I am assuming it will have been a basic Amazon one.

 

Another thing I have noticed which was not an issue with the temporary Dell system but is with this HP one is that Windows Hello does not work on the web cam.

The cam works, can do zoom etc, the IR lights come on when you try and log in but it says there was an error with the camera.

I have traced a long USB from the back of the system to a non-mains powered USB splitter which splits to kb, mouse and up to monitor, then from monitor, web cam is plugged in.

If I directly plug in the web cam to the PC, no issues, so clearly it also does not like the length of the USB lead, but as I say, worked fine on the temporary Dell system. Very odd.