Apple Event: May 7th at 7 am PT

Looks like no one’s replied in a while. To start the conversation again, simply ask a new question.

Level 1

2 points

Display interface lag on 4k DELL P2715Q monitor MacBook Pro Retina, 15-inch, Mid 2015

Is anyone experiencing issues with the outlined setup on the DELL P2715Q or any 4k displays?

My issue display performance is compromised and I’m having trouble switching between dialog windows, drop-down menus in the OS menu bar, very very heavy lag on any mission control action, and general performance lag of the OS as a whole. Sometimes I get better performance with near predictable 60Hz response and sometimes very very poor performance almost unusable.

I have had this exact same monitor (DELL P2715Q - 3840 x 2160) running with no issues on my older mbp mid 2014 with the older Graphics card with no issue whatsoever.

What I have tried:

Toggle all possible resolution combinations on both native display and tethered display
Exhaustive searches on Google and Apple threads for this issue
Disabling all non essential start up items
Different display cables
Different 4k monitor: the DELL P2415Q running at all configurable resolutions)

Is this possibly third party application interference?

This is a work computer so I’m required to run some third party applications.

Symantec Norton ™ Security
Mozy Enterprise backup solutions
Dell KACE Agent

System configuration:

MacBook Pro (Retina, 15-inch, Mid 2015)

Processer 2.8 GHz Intel Core i7

Memory 16 GB 1600 MHz DDR3

Graphics AMD Radeon R9 M370X 2048 MB

Built-in Display

15.4-inch (2880 x 1800)

AMD Radeon R9 M370X 2048 MB

DELL P2715Q Display (running at 60Hz)

27-inch (3840 x 2160)

AMD Radeon R9 M370X 2048 MB graphics

MacBook Pro with Retina display, OS X Yosemite (10.10.4)

Posted on Aug 7, 2015 10:49 AM

Best reply

MrApe

Level 1

4 points

Posted on Feb 15, 2017 2:21 AM

Though the post is a bit old, I have the exact same monitor and just found, that using scaled resolutions with a 13" MBP (early 2015) causes serious performance issues. Just use 1080p or 2160p. That [^almost] solves the problem for me.

Hope this helps.

Jonas

[^almost]: animations are smooth now, but there's somtimes a short "thinking break" before animation starts.

View in context

22 replies

bsouthga

Level 1

5 points

Dec 8, 2015 8:53 AM in response to MRusczyk

If anyone is still having this issue...

The solution for me was to set "MST" to "OFF" on the display itself, having MST in primary or secondary limits the refresh rate to 30hz.

see the manual for more info http://cdn2.bhphotovideo.com/lit_files/104995.pdf

swt83

Level 1

0 points

Dec 11, 2015 3:04 PM in response to bsouthga

This is the answer right here. Turn off "MST". It took me hours to find this answer. I have a brand new 2015 Macbook Pro and was still getting 30hz and was about to lose my marbles.

Dec 15, 2015 10:58 AM in response to MRusczyk

I just got this monitor P2715Q to use with my new rMBP, I tried everything, changed cables, turned off "MST" in monitor settings and was still stuck in 4K 3840 x 2160 @ 30HZ.

I discovered my issue was the Gen 1 CalDigit thunderbolt station that I used as a hub for the monitor, ethernet and keyboard. Having the hub connected will limit the refresh rate to a max of 4K @ 30hz.

A direct connection from my macbookpro mDP to DP to the monitor resulted in 4K at 60hz.

So just to add to the knowledge base if you are using a thunderbolt station from caldigit it will not pass 60hz to the monitor, I suspect it is because of the multiple devices (ethernet and keyboard in my case) tied to the same thunderbolt port.

Dec 22, 2015 9:07 AM in response to MRusczyk

Experienced this same issue with the Dell P2715Q, found a quick solution. In the monitor settings change Response Rate from Normal to Fast.

ifwdev

Level 1

0 points

Jan 9, 2016 3:28 AM in response to bsouthga

Thanks bsouthga!

Disabling MST didn't immediately enable 60hz for me, but once I changed resolution to "Default for Display" it worked!. I don't recall ever selecting "Scaled" - maybe has something to do with the fact that System Report says 1920x1080 @ 60hz but the screenshots (and my eyes) are clearly in 4k @ 60hz.

No hardware adapter required 🙂

Scenid

Level 1

4 points

Jun 9, 2016 4:56 AM in response to MRusczyk

I had extreme lags when using the 4k DELL P2715Q with my MacBook Pro (Retina 13", Early 2015). Thought at first, that it was the Intel Iris Graphics 6100, but the problem was solved by simply using a Mini Displayport cable instead of the HDMI I used for my previous monitor. HDMI is apparently not able to transport all the data needed for 4K. Now the transitions are still a bit off, but I don't get sick anymore when looking at the screen and I can work with it. 🙂

Sep 30, 2016 6:37 AM in response to ahg623

The P2715Q didn't lag with my setup in the "Scaled" mode. However, the system became a bit laggy when running pure 4k Resolution (not scalled). It became worse when I connected a second monitor. I am currently working in app development so I kind of bare with it.

The P2715Q is connected via display port 1.2

and my Samsung 4k via HDMI (laggs more).

Display interface lag on 4k DELL P2715Q monitor MacBook Pro Retina, 15-inch, Mid 2015