Question System gets unstable when plugging in 4K monitor

[Wanderers]

Hi there,

I have been upgrading my computer with a number of new components:
Motherboard: ASRock X570 Phantom Gaming X
Processor: AMD Ryzen 9 3900X
Memory: HyperX Predator Black 64GB kit (4x16GB) 3600MHz DDR4 CL17 DIMM XMP Desktop PC Memory (HX436C17PB3K4/64)
Graphics card: Radeon Pro W5500 8GB
Monitor 1: NEC Multisync PA271W
Monitor 2: LG 4K (not sure about the exact model number)

I had some initial problems where the motherboard did not recognize the memory, even though I specifically chose the memory as it was listed as being compatible with this motherboard. I previously tried some other memory (2x32GB) and could not get that to work at all. With the current setup, I managed to get it to work by first putting in two of the four modules, then applying the XMP settings, and then adding the additional two modules.

I do have one remaining problem, however, and I am not sure how to address it: the computer works fine if I plug in my NEC monitor (native resolution 2560 x 1440 ). However, as soon as I plug in my LG 4K monitor, either individually or together with my NEC monitor, my computer gets very unstable. The computer does not properly boot and restarts a number of times. Eventually, it sometimes, but not always, manages to boot but it looses the XMP settings. When it does eventually boot, it runs the memory at 2400 MHz instead of the 3600 MHz it is supposed to run and it resets its clock. When I go back in the bios to again apply the XMP settings, I do not get a signal on the monitor, the computer keeps on restarting and eventually looses all Bios settings again if I manage to get a signal on the monitor at all.

The graphics card should be very capable of running a 4K monitor (in fact it can run four 5K monitors). The problem is occuring on boot so it does not appear to be related to an OS driver. I have upgraded the motherboard firmware to the latest version (3.8) and am not aware of any firmware for the graphics card.

It almost appears there is a a conflict between my graphics card and the memory, but am not familiar with such a problem and have not yet found any information on such a problem.

Any advise on how to troubleshoot or fix this problem?

Thank you!

Johan

 

[rgd1101]

make and model of the psu?

 

[Wanderers]

The PSU is a bit older. It is a Corsair HX1050 and is probably about 7 years old at this point in time.

Interesting that you ask that question as I did an experiment a few hours ago, inspired by something else I read on this very rich forum. My PSU has a number of cables directly built into the PSU as well as a number of modular cables. There is a PCIe cable as part of the built-in cables, but there are also multiple modular PCIe connectors. In my install, I had used the built-in PCIe cable. What I tried earlier today is to unplug the hardwired PCIe connector and instead use a modular one. This appears to have fixed the problem and I am now able to run both monitors. (Let's hope it sticks as I had some instability before).

I would not have expected a difference and was trying to minimize the number of cables used, but can imagine that the modular cable somehow runs on a different circuit og and that there may be a power overload on the hardwired one which I do not have on the modular one. I am just guessing based on what I am observing and have no knowledge about how PSU's work.

 

[rgd1101]

possible the modular cable run from a different rail. at least you got it running.

 

[Wanderers]

I just looked it up and this is a single-rail PSU, so should not have made a difference. I agree with your comment that "at least I got it running" so won't loose sleep over why it didn't work in the first place.