Computer won't boot when using DisplayPort cable

[B16CXHatch]

I recently bought a new monitor. It's an Acer Acer K272HUL (Dbmidpx). There's more than one K272HUL, mine's the "frameless" 1440p IPS model. It comes with a DisplayPort cable in the box and supposedly DP is the superior interface so I used it. All was fine at first. The monitor doesn't auto switch and defaulted to DVI so I had to take care of that first but other than that, it worked perfectly.

That is, until I restarted the computer. Wouldn't boot right away. Keyboard/mouse lights were freaking out, but after about 20 seconds of that light show, it started. I thought that was weird and restarted again. Another light show for about 20 seconds then it started. I tried the other DP ports and same result until eventually on all ports, it wouldn't boot at all.

I switched to HDMI and bam! Booted just fine. I had my TV on a DP to HDMI adapter since my old monitor was HDMI only so I broke that adapter back out and tested it. Computer booted fine with it too. Plugged the DP cable back in and no boot yet again. Well, I read that cheap/bad DP cables can actually cause a computer not to boot. Off to Amazon.

New cable comes in and first boot is fine, then freak out light show, then nothing again. Great, another crap cable. Returned it and bought another more expensive, extremely high rated cable AND same result only it skipped the light show. Boots first time, then goes straight to not booting but with a new twist! The other two cables, my computer would do the usual fans wide open at power on, then slow down to the profile's speeds, even when the computer failed to fully POST. With this newest cable, my last attempt, the fans stayed wide open. I shut it off and switched back to HDMI. This time though, I was greeted with a message saying "Overclock failed, Press F1" blah blah blah. Of course, it had nothing to do with my overclock (which at the moment is just having XMP enabled).

I've pretty much decided DisplayPort is way overrated and for my purposes, HDMI is fine. I get 1440p @ 75Hz with no problems (monitor is factory 60Hz). All I seem to miss out on is 10 bpc color depth. I honestly didn't notice a difference between 8 and 10 anyway.

I'm still curious as to what's happening though and just wonder if anybody has any idea. I still kinda want it to work. Is it three bad cables in a row? Is it the monitor? Or could it be my video card? I would greatly appreciate any insight.

Thanks!

BTW, specs:
ASUS Z97A/USB 3.1
Core i7 4790K
16GB Corsair Dominator Platinum DDR3 1866MHz RAM
EVGA GeForce GTX 1060 6GB SC Gaming (Single Fan)
A GTX 1080 will soon replace it.

 

[VincentP]

I'm pretty sure this has nothing to do with DisplayPort or the cable you are using.
I would reset the BIOS to default as a starting point and run your RAM at specified speed (DDR3-1600 for the Core i7 4790K) until it is stable.
You also haven't mentioned your power supply, which is the most likely culprit.

 

[B16CXHatch]

Well, considering this problem literally only happens when DisplayPort cables are used, I'm pretty sure it has absolutely nothing to do with my PSU or RAM speed. If I use HDMI or DVI, it's fine. Heck, I start the computer with DisplayPort disconnected and then plug it in, it will work. The problem only exists if I have a DP to DP cable plugged into the video card and monitor during startup.

 

[B16CXHatch]

OK, finally had some time to do some more extensive testing. The main problem does indeed seem to be either the cables or monitor. However, the video card seems to be a secondary problem, kinda.

So, what I did was dig out my old GTX 770 (the only other video card I have at the moment with DisplayPort) and also went and grabbed my HTPC. I put the 770 in my HTPC first (it normally has a passively cooled GT 720) and tested the monitor with a DP cable. It worked on the first try so I restarted the computer several times and it continued to work. So, I swapped video cards. I put the 770 into my main rig and put the 1060 into HTPC. Well, the main rig still didn't boot when using DP on the 770 but booted fine using HDMI. Thing is though, the HTPC also didn't boot when using DP on the 1060 but booted fine with HDMI. It was exhibiting the exact same behavior as the main rig.

Now, I said the HTPC would boot fine using DP with the 770, but there is still some weirdness. There's an LED on the motherboard labeled CPU_LED that normally only lights up during the boot up sequence and cuts off once Windows starts to load. When I would shut the system down with the DP cable plugged into the 770, that light would stay on and if you pulled the DP cable out, the light would immediately cut off. This light stays off using anything other than DP on any card.

So, I'm still not entirely sure, but I'm gonna say the problem is likely the monitor or DP cables. I really wish I had another monitor with DisplayPort to test. Oh, well. Like I said, HDMI does the job so I'm just not gonna worry about it. I might give it one more try when I get a 1080 but judging by the fact that both the 770 and 1060 have this problem on the main computer, it's probably gonna have the same results.

And in case it matters, the HTPC's specs:

EVGA SuperNOVA 550 G2
ASUS P8Z68-V/Gen 3
Core i5 2500K @ 4.2GHz
8GB Corsair Vengeance LP DDR3 1600
EVGA GeForce GT 720 Passively Cooled Version (was removed for this testing)
EVGA GeForce GTX 770 2GB SuperClocked with Reference Cooler (only used for testing, too big and noisy for regular use)
and of course the same video card as the main rig was also used for testing.

And since I left it out previously, the main rig uses an EVGA SuperNOVA 850 G2 PSU, which again, probably has nothing to to do with this. Using HDMI, I can play BF1 for hours with no problems.

 

[Koldtoft]

I am having the same problem. I have 3 monitors connected. 2 x 27" Dell 4K display and 1 x 31.5" Samsung 4K display. I have a GTX980 with 1 HDMI output, 3 DP outouts and one DVI output. Needless to say, I need at least one (preferably two) DP cable(s) to connect all 3 monitors at 4K resolution.

To make it worse, I am running my computer from a separate room (for noise reduction and minimalism reasons), and long high-end cables are expensive.

I have been using Clicktronic High Quality 4K DisplayPort cables for ages and never had a problem. But recently I moved my computer to a new box, which means, I also got a new motherboard and also I updated windows 10. And then the problems started

Now the computer won't boot up when any one of the monitors are connected with a DP cables. I can unplug the DP cables, boot the PC with HDMI only and then plug the DP cables back in, and that works fine, but needless to say, that is a pretty retarded "solution".

Reading the above posts, I guess I am going to mess around with the BIOS settings, as I think maybe the problem is caused by my new motherboard. I am using the same power supply, same graphic card, same cables and same monitors. So what's new is the motherboard.

Any other advice or input would be greatly appreciated. I will report back here, once I find out mere.

 

[John_822]

I am having the same issue. hdmi works just fine if i use the display port my light dvd and fans wont shut off ...

 

[calvin79]

Same problem here! Probably more bizarre.

I have two dell monitors: an old U2412M with only DP in, a new U2717D with DP in and out. Monitors are driven by a GTX 1060 with 3 DP ports.

I love the locking mechanism of DP cables (for the exact reasons i hate HDMI) as well as the daisy chain concept. So obviously i prefer PC <-> U2717D <-> U2412M. I found two old but decent DP cables and hooked up the monitors like that. Apart from the U2412M takes a few more seconds to light up, everything is fine.

Well not until i get a cheap but slightly longer DP cable to connect the PC <-> U2717D (because the old cable is slightly too short):
- PC <- cheap cable -> U2717D <- good cable -> U2412M: computer boots up. No display at all. U2717D says "no DP signal". U2412M sleeps.
- PC <- cheap cable -> U2717D: The monitor complains "no DP CABLE". PC won't boot up. The normal power LED lights up for 2 seconds and goes off for 10 seconds, and repeat. Casing fan runs for 1 second and goes off for 11 seconds, and repeat. CPU fan runs for quarter of a turn, and goes off for 12 seconds, and repeat. The moment i unplug the DP cable from the PC. It boots up automatically but obviously i don't have any monitor to use.
- PC <- cheap cable -> U2412M: works fine!!

I was googling crazy to see if there're different versions of DP cables but to no avail. The cheap cable works on the U2412M so i can't say it's totally defective.

Anyone has any ideas?

 

[Alastair_1]

To add to this - i'm having the same problem. Upgraded from 1070 to 1080ti, when powering on with 1080ti installed and DP connected to screen the RGB lights just blink and fans spin every few seconds and it doesn't boot. Plug in with HDMI and everything works fine. (embarrassing when it booted first time in the store...). Plug the 1070 back in and it boots fine with DP connected - so something to do with the graphics card...

Will try different DP cables and perhaps different monitor if possible, but reading above don't think this will help.

If anyone has a solution, grateful to know as I would like to use the card for VR and screens so need all the ports...

Thanks in advance

 

[B16CXHatch]

Wow, I had forgotten about this. So I never actually solved the problem per se but I'm going to just blame the monitor cause I just don't think I got that many dud cables in a row. I built a new computer shortly after I started this thread but only recently tried DP cables again.

So my new computer will boot with DP cables but only if my monitor is on. If I power it on with the monitor off, it will be stuck until I actually turn the monitor on. I hit the power button on it and walked away for a few minutes. When I came back, I turned the monitor on and the computer started POSTing. This thing boots in like 10 seconds so I knew something was up. Kept testing and if the monitor is on, instant boot. Off, hang until monitor is powered on. Every time. Also, when the computer is running and I turn the monitor off, when I turn it back on, the computer acts like I disconnected the monitor. The Recycle Bin (the only icon I have on the desktop) gets moved and the background image freaks out for a second. With DP, the computer seems to be unaware of the monitor if it's off but doesn't have that problem with HDMI.

So yeah, I'mma blame the monitor and say something's not right with its DisplayPort.

And again, if it matters, specs:

EVGA SuperNOVA 850 G2 PSU
ASRock Z270 Taichi
Core i7 7700K
G.Skill Trident Z 16GB (2x8GB) DDR4 3200 RAM
EVGA GeForce GTX 1080 FTW2 with updated BIOS (changes default VRAM speed to 11GHz)

 

[yusei.watanabe]

Some Displayport cables seem to feedback power supply into the computer via the graphics card, preventing proper shutdown and in some cases, damaging the hardware. This problem is quite widespread it seems. Search "displayport pin 20".