Just received my p2815Q (3840×2160) and noticing the input lag is horrible. I understand this is a 30hz monitor, which I assumed just meant the refresh rate is 30 frames per second. I am a programmer and my job requires lots of mouse movements, clicking on various things, etc and there is a very perceptible 'catch up' that the mouse is doing whenever I move it anywhere on the screen. I have DPI scaling set to 150, all the text is crystal clear and looks beautiful, but this input lag is making this monitor feel unusable. Is this a configuration issue of some sort or has anyone else notice this as well? Another note, even if I change the monitor to 1920x1080, I still have the same input lag, even at 60hz. Even as I type this, there is a slightly noticable lag between when the key is pressed and the text appears in the box.
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I got a P2815Q about a week ago and I would agree that the issue is input lag with the display. I run a 4 monitor setup and the only monitor with the delay is the P2815Q. If the mouse drivers were an issue, it'd be evident on all the displays.
I find that the delay means that I automatically slow all mouse movements as I near the target to prevent overshooting. I appreciate that the targets are physically smaller but I've compared moving the pointer to a point on the background image of the P2815Q with moving to the same point on one of the other displays (all operating at 1920x1080). On the latter, you can go straight to the point but on the former there's usually some overshoot and then correction.
If I were to speculate, I'd suggest that the monitor has a significant processing delay to convert the video feed to the pixel switching. If I were to simply watch motion on the display it'd be fine - 30Hz is similar to standard TV broadcast - as every frame is delayed. However, when controlling things, the delay causes a problem with the human feedback loop.
The delay is also evident when typing text too but, again, only on this display.
BTW, I'm using the DisplayPort input, although I was using the Mini-DisplayPort until earlier today. There is no difference in behaviour.
Personally, I'm borderline on whether the lag is acceptable. For me, the benefits of the high resolution just about tip the balance but I suspect most users would not find this issue acceptable.
(1) Test the wired USB mouse on all three P2815Q bottom USB downstream ports
(2) Test the wired USB mouse on the P2815Q back USB downstream port
(3) Test the wired USB mouse on a USB port directly on the computer
Post your results
Due to the hardware architecture, the mouse lag is a result of the P2815Q requiring 100 ms to process video data. If you have this complaint, your only recourse is to return the monitor for refund. Outside of the initial 30 days from the invoice date, it will take manager approval to get a refund.
Hi Tom, I ran into the same issue you did. I have a mini displayport cable hooked up from my alienware to the monitor and I couldn't get anything to come up on the monitor, even though the laptop recognized the monitor. I've tried multiple connections. Right now I have it connected via HDMI cable to my laptop. Crisp and clear screen but that obnoxious input lag. I bought 2 monitors actually, but haven't opened the second box so that I could return, and am not sure if the monitor is defective or if every P2815 has this input lag associated with it. When you drag the mouse across the screen, do you notice theres a slight lag with it compared to any other monitor?
I am using an Mac Pro Late 2013 to connect to the Dell P2815Q monitor. I didn't notice the mouse movement. I am using an Mac Pro to drive the monitor. If have the use of HP laptop with an display port. When I hook the cable that came with the dell P2815q, the monitor works! If I use an display port to mini display port and an thunderbolt cable from apple, it does NOT work! So, is the problem the apple thunderbolt cable? the display port to mini display port adapter?
Do you have the mouse and keyboard plugged directly into the monitors USB downstream ports? If yes, connect them directly to the computers USB ports and retest for lag. What is the monitor serial PPID number?
We cannot assist you in this. We do not test our monitors on apple proprietary hardware. Check the apple Discussions Forum for help from other apple users with our products: https://discussions.apple.com/index.jspa
I am using a Macbook Pro and the monitor displays great, but has the same lag. I tried using all 3 connections: Displayport, Minidisplayport and HDMI. How did you get yours working?
I ended up trying just about every configuration there was, different inputs, different PCs, different mouse/keyboards (even noticed keyboard lag on the monitor when typing)
I had ordered 2, so even opened the second box, with no such luck, it also had the lag.
I think for general use, people tend to get used to it but I do programming so mouse movements are constant and I need to have accurate mouse tracking (i.e. when there's mouse lag you 'overshoot' what you want to click on and have to drag back to it)
I ended up returning the 2 monitors which is too bad, I really LOVED the clarity of 4k, but theres obviously some issue there.
I did the same as you as well, dropped down to 1080 @ 60hz just to rule out it being some 30hz issue. Same thing @ 60hz.
This sounds more like the mouse drivers. I have had issues with certain logitech mice and their resolutions. I.e. if it is only 150dpi mouse (or thumball like I use), and you have turned up all the mouse accelerations, it has to skip to catch up with where the pointer now is.
Are you using OSX or Windows, and which version? Are you using native mouse drivers, or Logitech/other installed?