U2415, three in chain, blink on/off

Hi Chris...thanks for your reply.

#1 by itself direct connect via DP1.2 cable to GPU...no blinking

#1 daisy to #2....both begin to blink after a minute or two

#1 daisy to #2 daisy to #3.....all three begin to blink after a minute or two.

Any thoughts?  Is my GPU capable?

I would start by turning everything off. Disconnect monitors 2 and 3 from the setup.

* Test monitor 1 by itself. Does it have the blinking issue? (Y/N)
* Turn the computer and monitor 1 off

* Add monitor 2 in a daisy chain:
Does monitor 1 have the blinking issue? (Y/N)
Does monitor 2 have the blinking issue? (Y/N)
* Turn the computer and monitor 1/2 off

* Add monitor 3 to the daisy chain:
Does monitor 1 have the blinking issue? (Y/N)
Does monitor 2 have the blinking issue? (Y/N)
Does monitor 3 have the blinking issue? (Y/N)

Can you test monitors 2 and 3 as  #1 in the chain? Is there another desktop computer to test them on?

Chris...I have tested every combination..with same result.

Thinking this might be caused by an older GPU, yesterday I decided to upgrade the majority of my system and purchased and installed:

CPU:  Intel Core i7 4790K

MoBo:  Asus Z97-A

OS:  Win 7 Pro

My 3 U2415s are all REV A02

I did retain Corsair HX650w PSU, which has more than enough power to drive my rig and Cooler Blaster 212+ to keep the i7 chill.

So...I essentially have a brand new and up to date system.

What is going on here?

The good news is that the random black screen blinking has decreased from once every 90 seconds/per screen to about once every hour or so.  

I also forgot to mention that I purchased a new GPU as well:   Sapphire Radeon R7 380

I hit "Post" to fast.

I meant to say that even after doing all of these upgrades to create a very current system, the screens all still randomly go to black and then back on, when in daisy chain.   No issues if running only a single monitor.

The good news is that the rate at which they black screen blink has decreased.   I did notice that when I was in the midst of copying 12 gig of files from one of my HDDs to my SSD the pace of blinking increased significantly, similar to what I saw before upgrading components.  How could this be impacting MST?

What is going on here?

Did you install the latest AMD driver for the Sapphire Radeon R7 380? If yes, the only other thing to try is to get three monitor exchanges there. Then, test all three replacements. You will have six there to mix and test. But by the end of testing, three will have to be sent back to Dell.

Hi Chris....I wanted to give you and the community an update.

I upgraded my GPU, again:

From:  Sapphire Radeon Nitro R7 360 2GB (new a week ago)

To:      Sapphire Radeon Nitro R9 380 4GB (yesterday)

Since I did the swap yesterday morning, I have only seen one monitor flash to black screen, once.  The new card is faster and has twice the memory capacity.  I don't know which of those features caused the change in behavior, but I am just glad the monitors aren't blinking, for now.  Based solely on my experience, it would appear that in order to daisy chain the U2514s, you need a reasonable recent  and powerful GPU card.  If this is the case, where does Dell disclose this is minimum system requirements?  Is there a Knowledge Base discussion on this issue?

QUESTION:  Can the included Dell DP to Mini DP cables be used to daisy chain?  After I saw some stability in the monitors I tried to use these cables to daisy chain #1 to #2 and #2 to #3, as I wanted to return the $27, 3ft Full DP to Full DP cables I bought at Micro Center.  Once I booted up, only #1 lit up and went to Window.  #2 and #3 flashed "No DP Cable".  I swapped both mini to full DP cables to see if one was bad, same result.  Why won't these work?

Thanks for your help.

I just wanted to add my 2 cents, since the blinking on my two Daisy Chained Dell U2415 was driving me completely MAD but now it is resolved.

Anyway, I am running:

Windows 10 x64

AMD Radeon R5 340X

HP Z220 Workstation

Two Dell U2415 monitors that are version A02.

I am NOT using Dell drivers and using the AMD drivers that come down from Windows Update only.

Basically, the monitors would blink randomly every once in a while with no "rhyme or reason" so sometimes one, sometimes both, sometimes every 5 minutes, sometimes every hour; but it was driving me crazy. I finally decided to unplug everything and decided to switch the cables as everyone has mentioned.

PREVIOUS CONFIG:

AMD DP --> Dell #1 mDP

Dell #1 DP --> Dell #2 mDP

I tried setting one to DP 1.2. Both to DP 1.2. Tried Dell drivers. Tried AMD drivers. Updating Drivers. Changing various settings, but always blinking.

NEW CONFIG:

AMD DP --> Dell #1 DP

Dell #1 DP --> Dell #2 mDP

I went ahead and did FACTORY RESET on both monitors and then enabled DP 1.2 on Dell#1. No more blinking and it has been in use for more than 8 hours, so it looks like that solved my problem.

I was using two identical cables from "Cable Matters" that goes DP to mDP, but the blinking stopped when I changed the initial cable coming out the video card. So my suspicion is that the DP to mDP cable somehow cannot handle all the initial throughput and I will eventually go 3 monitors, but now I know to try the DP/mDP cable switch.

Thanks and just sharing, since I was checking the boards for solutions...

I just bought a second screen Dell U2515H (one year after the first) and I had the same black screen problem. I have a Surface Pro 3 with a docking station.

At first, I had activated the DP 1.2 on both screens and the problem was very frequent. Then, I disabled the DP 1.2 on the second screen (Intel graphics card) and the problem was less frequent. But too common, only a few minutes before the black screen.

I then reversed the screens by directly connecting the new screen to the docking station (initially the old one) and the problem does not happen at the moment.

In Device Manager, I noticed that there was a difference between the two screens:

Old screen: DELD06E

New screen: DELD06F

Maybe Dell corrected the problem on the new screens. Can you confirm ?

I just modified the configuration, I have to check for a while before confirming that it works.

Thanks for this answer - I have two Dell U2717D and had DP -> mDP and DP -> mDP and had both flashing constantly. Been using it like that for over a year. Just switched the first monitor to DP -> DP and it no longer flashes! The second monitor is still mDP -> DP and unfortunately still flashes, but less often. I am on a Dell Precision 7510 so latest hardware Windows 10 x64. I have used the same setup on a Precision M4700, Precision M4800 (Windows 7 x64) with the same blinking. My coworkers (at least 4 of them) have had the same setup and the same blinking on daisy chain. Not sure if it is the cable, or these models of monitors, but they definitely have an issue. Solution is not to use mDP it seems. Not sure how it slipped past testing!

I have two U2415 daisy chained and ran into the same issues many reported with 1) display flickering 2) second monitor fails to go into sleep mode. The flickering was only a few times a day in the beginning and progressed to almost constantly flickering (once every ten or so seconds).

After some tickering around, found the culprit to be the cable connecting the first and second monitor (DP to DP). Both problems solved after switching to a different cable. (My monitor doesn't come with any DP cable)

It seems the monitors are very picky with the quality of the connecting cable. Even the 'bad' cable is supposed to be high quality and dp 1.2 rated but I guess it wasn't good enough. 

Suggest buying the best cable you can find for the job and get a spare one from another manufacturer just in case.