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External Monitor Lag

L

leland_07

macrumors newbie
Original poster
Apr 22, 2018
14
3
Hi guys. Any thoughts on a laggy mouse (cursor) experience on external display vs laptop display? It's set up as an extended display and when I move the cursor over and begin to work it's just not smooth.

Is there a difference in HOW you connect an external monitor? For instance, would using my thunderbolt 2 port be a "better" connection to my monitor? I know Chrome can have it's issues but this is happening with Chrome closed. I was really excited to have an external monitor but this has me bummed.

Macbook specs:
Macbook Pro (Retina, 15-inch, Mid 2015)
Processor 2.5 GHz Intel Core i7
Memory 16 GB 1600 MHz DDR3
Graphics AMD Radeon R9 M370X 2048 MB

External display:
Samsung U32H850UMN
https://www.amazon.com/gp/product/B071Y6SWGT/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

Browser:
Chrome Version 68.0.3440.106 (Official Build) (64-bit)

Mouse:
Logitech G602

Connection:
HDMI from laptop to monitor
 
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There shouldn’t be a difference between using a mouse on an external monitor over an internal, and different connection types (HDMI, DisplayPort, and so on) shouldn’t impact Bluetooth functionality either.

In my opinion, it sounds like you may simply have a bad HDMI cord that is giving poor signal to your monitor and causing the monitor to lag. Especially if the laptop is plugged into the monitor and the mouse works fine on the internal screen but lags on the external screen. Try swapping out the cord with a different brand cord and see if the issue continues.

Also, there is a chance that the HDMI cord is of poor quality or defective and it is not properly shielded, and that could cause it to interfere with Bluetooth devices too. Same thing here, try a different cord to see if the issue continues.
 
Depending on the hdmi adapter used, it is likely only working in 30hz mode. So yes, the way it's connected matters. only displayport based adapters ( even if output is intended to hdmi ) can do 60hz at 4k, not usb alt mode hdmi.

edit: ignore most of what I said! I didn't see the 2015.

yes, the hdmi port on 2015 is not able to output 60hz 4k, you need a mini display port cable of some description to get the most out of this monitor.
 
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Just swapped out the HDMI and tried both ports on the monitor. Same result. It's like it's just laggy. The best way to see this is to left-click hold on a folder and drag it back and forth across the screen. The laptop shows very snappy and immediate response but when you drag the folder back and forth on the external monitor you can just tell that it's delayed.

Thank you for trying to help. This is hella frustrating.
 
leland_07 said:
Just swapped out the HDMI and tried both ports on the monitor. Same result. It's like it's just laggy. The best way to see this is to left-click hold on a folder and drag it back and forth across the screen. The laptop shows very snappy and immediate response but when you drag the folder back and forth on the external monitor you can just tell that it's delayed.

Thank you for trying to help. This is hella frustrating.
Click to expand...

hdmi can only do 30hz 4k on 2015 due to hdmi 1.4 port, needs 2.0 to do 60hz. Only displayport ( mini display port cable into thunderbolt port ) can do full 60hz 4k on that gen.
 
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leland_07 said:
Just swapped out the HDMI and tried both ports on the monitor. Same result. It's like it's just laggy. The best way to see this is to left-click hold on a folder and drag it back and forth across the screen. The laptop shows very snappy and immediate response but when you drag the folder back and forth on the external monitor you can just tell that it's delayed.

Thank you for trying to help. This is hella frustrating.
Click to expand...
When I made my comments, I totally didn’t realize you were trying to use a 4K monitor on you MacBook Pro. In this case @iMacDragon had a good point, a mini-DisplayPort cable will likely be a better option than an HDMI, due to the limitations set on the HDMI port on that model MacBook Pro. Give that a shot and hopefully youll have better results
 
Thank you guys. I have an adapter (see attached pics) and DP cable that came with my monitor. However, in researching this earlier I believe I read that mini-DP and thunderbolt are not the same even though they "fit" one another?

So should I even try this connection? Don't want to damage anything.
[doublepost=1536293741][/doublepost]Sorry. Trying to upload pics but site is being slow...
 
leland_07 said:
Thank you guys. I have an adapter (see attached pics) and DP cable that came with my monitor. However, in researching this earlier I believe I read that mini-DP and thunderbolt are not the same even though they "fit" one another?

So should I even try this connection? Don't want to damage anything.
Click to expand...

A mini dp cable will work in a thunderbolt port, a thunderbolt cable will not work in a mini display port.

https://support.apple.com/en-us/HT204149

i.e. go ahead, it's what you want to use ( pic didn't attach, but presuming it's a mini dp to full size dp adapter. )
 
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GOT IT! BOOMSHAKALAKA!!! DP did the trick. Man, f*cking killed it. What a relief!!! Thank you so very much.
[doublepost=1536297365][/doublepost]Reading up on ports and such. Been a Windows user my whole life and got my first Mac just a few months back. I have so much to learn. Thanks for the links.
 
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One thing that helps overcome the speed issues is if you got to System Settings --> Mission Control, turn off Displays have separate Spaces. Of course, this means a loss in functionality as you can't screenshare content in the external monitor separately. However, this does overcome all the lag problems.
 
I determined this is caused by a voltage issue.
I used to have this issue when connecting my Cintiq 21UX to a DVI-D to DVI-I converter to my GPU, at first caused some lag but then I uplugged everything and this time I ensured the connection of the converter and the card were completely secured and well plugged, and the lag disappeared. Maybe there is probably some noise on the connection that causes the mouse to move like that
 
Had the same problem and solved it!
MacBook Pro 2015, external monitor connected via HDMI, wireless Logitech M705 mouse with Nano Receiver connected via USB.
All I needed to do was to plug the mouse receiver into the USB port on the left instead of the one on right, next to HDMI port.

Painter2002 said:
Also, there is a chance that the HDMI cord is of poor quality or defective and it is not properly shielded, and that could cause it to interfere with Bluetooth devices too.
Click to expand...
Thank you, Painter2002!
 
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I had the same issue before. Try go to System Preference --> Displays. You will see 2 windows, one for your display and one for the built-in display. In your display's panel, choose default for display, let it refresh, then choose another scale, then let it refresh, then choose whatever scale you want. That fixed the issue for me.
 
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scandalousapple said:
choose default for display, let it refresh, then choose another scale, then let it refresh, then choose whatever scale you want
Click to expand...

Holy cow. I can't believe it, but this fixed the problem for me. I had the problem with my 4K external monitor, and I was getting bad delays with four different mice / track pads. It was worse with the Bluetooth mice.

Macbook Pro, 16", all upgrades.

This fixed it, for the current session at least. Crazy.
 
I'm having similar problem with 2019 MBP. Been using Bluetooth mouse with it for months without any problems, with external display. Just got new 4k 27" display, and now have serious mouse lag.

I've ruled out Wifi interference, and when disconnecting ext. display the issue goes away.

Is it possible display is using too much power? Connected via HDMI and USB-C adatper, any suggestions appreciated.

UPDATE: just found this thread...so 60hz compatible HDMI cable and USB-C adapters is a real spec?

What it was --- the cables I was using couldn't handle 60hz. Got some expensive USB C to HDMI cables and the issue went away. Sorry for not posting this earlier - completely forgot.

It is definitely related to the resolution and refresh rate.

The Anker USB C dock could only handle 30hz - not 60 for whatever reason (even though it said it could). Either that or it didn't like the Acer monitor.
Click to expand...

15" MBP 2019 MacOS 10.15.6 BenQ PD2700U display.
 
Last edited:
jimtron said:
Is it possible display is using too much power? Connected via HDMI and USB-C adatper, any suggestions appreciated.

UPDATE: just found this thread...so 60hz compatible HDMI cable and USB-C adapters is a real spec?
Click to expand...
*Never* interface a computer monitor via HDMI unless you have no other choice. Get a DP cable, and use that. Something like https://www.amazon.com/gp/product/B01J6DT070 or the equivalent.
 
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I have a MacBook Pro 15" 2017, 2,9GHz Quad I7 with Catalina 10.15.7, connected to a Benq 32" 4K monitor via Display Port to USB-C cable. With my Magic Mouse I experienced a slow mouse pointer lagging behind or freezing. Sometimes the mouse would even disconnect. My bluetooth trackpad worked perfectly all the time. Apple Support advised me to boot in safe mode, and that solved the problem for a short time - as I realised afterwards - until I connected my Benq monitor again. Because of the above replies, I started experimenting with other connection types and cabes. Now I have connected the monitor with the USB-C cable that was suppied with the monitor, and all problems are gone.
Thanks to all above to put me on the right track to solve the problem.
I will give feedback to Apple Support tomorow afternoon in a planned call.
 
Hello, can you update us on what happend? I'm experiencing the exact same problem. I'm also using a Benq monitor but it's FULL-HD. Did you manage to fix it ?
 
Lucky14 said:
Hello, can you update us on what happend? I'm experiencing the exact same problem. I'm also using a Benq monitor but it's FULL-HD. Did you manage to fix it ?
Click to expand...
Sorry for the late reply. As I explained in my previous post, I experimented with several cables, but the only one that solved my problem was the shielded USB-C to USB-C Thunderbolt cable, that was supplied with the monitor. All problems are gone since that change. If your monitor doesn't have that USB-C connection and cable, I would suggest you try with another shielded cable, e.g. HDMI. I am afraid that with this type of interference, there are no obvious rules. It boils down to trial and error. Hope this helps.
 
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