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S2716DG, GTX 970 doesn't always work above 85Hz
I know there are some threads about this issues already but none of them really helped me. Yesterday I got my new S2716DG and it appeared to be working fine except I was unable to go past 85 Hz at 2560x1440 resolution on my GTX 970. Whenever I selected 100,120 or 144Hz it would just flicker non-stop or go into power saving mode. After several tries and switching Nvidia G-sync off and on again it started working at 144Hz and all other refresh rates however after I rebooted my PC it again won't go past 85Hz. I am using DP cable that came with the monitor and it did work fine for hours yesterday at 144Hz so I'm just trying to figure out why doesn't it always work properly.
Celador
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March 5th, 2018 09:00
In case anyone has this issue and find this thread - the solution was to buy a new cable. Bought literally the only available cheapest cable and now everything works fine and it switches to any refresh rate. Also fixed pixelation issue.
Fun fact - the new cable says "protocol display port 1.0" but apparently it doesn't make any difference. On some forums it is explained that all displayport cables are capable of using any version of displayport and only the port on monitor and videocard matter.
DELL-Chris M
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March 1st, 2018 07:00
* When was this monitor purchased?
* Was this monitor purchased directly from Dell?
* What is the 20 digit s/n and A0x revision? Check the back label
The ability to do the higher Hz (85Hz/100Hz/120Hz/144Hz) is built into the monitor hardware. I doubt that the monitor is defective. The GTX 970 released in September 2014 is most likely the problem. Understand that even the GTX 980 video cards are on the edge. Some have the required 586MHz pixel clock, others do no not. Depends on the manufacturer (EVGA, Asus, etc.). The video card pixel clock must be 586MHz or higher to do 2560x1440 144Hz.
* Open the Nvidia Control Panel
* Go to Display- Change Resolution- Customize- Create Custom Resolution
* Look on the bottom right for the Pixel clock for your video card
Celador
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March 1st, 2018 09:00
Hey. Thanks for answering.
I purchased the monitor literally yesterday.
I bought in a reputable shop where i usually buy pc hardware and phones/tablets.
On the back label it says manufactured august 2017 CN-0Y44M5-QDC00-78T-0WYU-A07 and i also added it to my products page on dell website where it says that the warranty is valid until 2020.
Yes i've read that 970GTX might be the culprit but then again - it does work after few tries above 85Mhz. Right now for example im running it at 120Mhz and can switch to 144Mhz without any issues. Even if it was an issue with 970GTX (which has pixel clock of 497Mhz) shouldn't it still run at least 100Mhz? Why would it work sometimes and sometimes won't? On other forums i've noticed people mentioning similar thing - either it doesn't work at all above 85Mhz or works intermittently even on 770GTX and above.
Last thing i wanted to mention is that sometimes monitor would flicker or switch off when i touch the display port cord. It seems that connection to the port on the monitor isn't firm enough and when i shake the monitor or the cord gets twisted it would flicker or disconnect. Could that be the culprit? Either the display port cord which came with the monitor or even the display port on the monitor itself?
DELL-Chris M
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March 1st, 2018 12:00
Even if it was an issue with 970GTX (which has pixel clock of 497Mhz) shouldn't it still run at least 100Mhz?
* No idea. We never tested it on the GTX 970. Nvidia told us the minimum for 144Hz was the GTX 980 and newer. So that is what we tested. Understand that there are mulitple versions of that GTX 970 around from different vendors. So naturally, the results will differ by vendor.
Last thing i wanted to mention is that sometimes monitor would flicker or switch off when i touch the display port cord.
* A quick test would be to get a retail DP to DP cable and see if it "fits" better or the same. I have never heard of the actual DP in port being defective.
Celador
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March 1st, 2018 13:00
Guess ill try another cable then. Even now when the table shakes slightly it would disconnect sometimes and i have to wobble it a bit.
I did connect everything neatly and i used the hole inside the stand, i didn't use any excessive force either. It is surprisingly hard to find another cable. All of them seem cheap.
Celador
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March 1st, 2018 15:00
By the way - when you go into Nvidia Control Panel->Display- Change Resolution- Customize- Create Custom Resolution it doesn't show your GPU pixel clock, it shows the pixel clock of the current settings. For 2560x1440 resolution with 24Mhz its 95Mhz pixel clock, for 60Mhz its 241Mhz pixel clock, for 85Mhz its 346Mhz clock and so on. For 144Mhz it shows 497Mhz and not 586.
Im not entirely sure where that information about 970GTX and 586 came but on Nvidia forums pretty much everyone says it can't be right.
DELL-Chris M
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March 5th, 2018 09:00
So the S2716DG DP to DP cable was defective? On both ends (monitor and video card ports), does our cable seat differently than the retail DP to DP cable that you bought?
Celador
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March 5th, 2018 10:00
Yes included cable apparently was defective. Also explains why the monitor would flicker when i touched the cable - i thought it was the issue with the port on monitor but it was something wrong with the cable. I did try to reconnect the included cable and connect it firmer or better on both ends but it didn't help and at some point the monitor stopped flickering when i touched the cable but i also couldn't switch to any other refresh rates at all after that. Im guessing that it was already defective and just broke completely at some point so the monitor could never use anything past 85Hz again.
The new cable is different in only one aspect - it has locking mechanism. There's a button on each end to unlock and remove it from the port. Also it locks in place easier than the included cable - i just slide it in and it locks itself in place.
Also on the cable included with the monitor it says "hotron" as a manufacturer. Is that normal? I mean it was in a sealed packet included with a monitor.