• Welcome to TechPowerUp Forums, Guest! Please check out our forum guidelines for info related to our community.

USB port in back of monitor causing graphics lag

Easy Rhino

Linux Advocate
Staff member
Joined
Nov 13, 2006
Messages
15,686 (2.32/day)
Location
Mid-Atlantic
System Name Desktop
Processor i5 13600KF
Motherboard AsRock B760M Steel Legend Wifi
Cooling Noctua NH-U9S
Memory 4x 16 Gb Gskill S5 DDR5 @6000
Video Card(s) Gigabyte Gaming OC 6750 XT 12GB
Storage WD_BLACK 4TB SN850x
Display(s) Gigabye M32U
Case Corsair Carbide 400C
Audio Device(s) On Board
Power Supply EVGA Supernova 650 P2
Mouse MX Master 3s
Keyboard Logitech G915 Wireless Clicky
Software Fedora KDE Spin
Okay is this a thing? I plugged in a USB Type B cable into the back of my monitor and attached it to my PC. I then plugged my keyboard (only) in the back of the monitor. All games lag now. I unplug the cable and everything is butter. Is this normal behavior?
 
Definitely, it is not normal behavior. I assume if you plug the keyboard into the PC where you had the monitor USB connected, all still works fine, right?

Did it (the monitor's USB port) used to work fine?

I don't know but since most motherboards have designated USB ports for the keyboard and mouse, I always use them.
 
Hrm, it seems to be inconsistent depending on what port it gets plugged into. This is the first time i am using the hub in the back of the monitor.
 
Something it pulling to much power and most likely sharing power with the monitor. High power draw monitor most likely lags.
 
Something it pulling to much power
In another scenario I might agree with that but the monitor's USB hub should be getting power through the monitor's power supply, which would be isolated from the computer. And keyboards - even backlit keyboard don't draw much power.

@ Easy Rhino - have you tried a different keyboard?
 
Low quality post by Zareek
Very odd indeed.
The USB port on the Monitor should be a straight forward pass through and shouldn't affect games or the Monitors performance.
The only possibility I can imagine is interference with your internet somehow causing the lag. Cables overlapping etc.
 
I would say it sounds like latency on the monitors USB hub. It might be looking like graphics lag because it's reacting slower, but I would suspect it's keyboard lag.

It could be that USB hub is a cheap design for things like charging and data transfer where the input can be laggy because you are not expecting immediate effect.

Best solution is a decent powered USB hub velcroed to the back of the monitor.

Or a single cable extender just for the Keys and use the monitor USB for lower polling devices.

I've seen similar effects with high-end Joysticks. They like a nice high polling USB connection like a mouse but on some motherboards and USB hubs you can generate input lag, The effect is a stick that has a stepped input feeling and it'll show in the configuration screens. Generally, I've seen it where a 3rd party controller or a cheap hub is used.
 
Last edited:
Try with a different USB cable from monitor <-> PC, the current one could simply be faulty.
Check if there's a specific driver for the monitor and if so, install it.
Check if there's a firmware update for the monitor, if so install it.

It could also be a hardware incompatibility between keyboard and monitor. These things aren't supposed to happen, but they do.
 
I would say it sounds like latency on the monitors USB hub. It might be looking like graphics lag because it's reacting slower, but I would suspect it's keyboard lag.

It could be that USB hub is a cheap design for things like charging and data transfer where the input can be laggy because you are not expecting immediate effect.

Best solution is a decent powered USB hub velcroed to the back of the monitor.

Or a single cable extender just for the Keys and use the monitor USB for lower polling devices.

I've seen similar effects with high-end Joysticks. They like a nice high polling USB connection like a mouse but on some motherboards and USB hubs you can generate input lag, The effect is a stick that has a stepped input feeling and it'll show in the configuration screens. Generally, I've seen it where a 3rd party controller or a cheap hub is used.

This is basically what I was going to say. I think we need a better idea of what "lag" means. Is it framerate drops or input lag?
 
Just out of curiosity, are you by chance using 2.4GHz Wi-Fi to connect to the internet and it's a USB 3.0 hub? If so, you could get interference from the USB 3.0 part on the Wi-Fi signal, but that's about the only thing I can think of that would cause this.
 
Older monitors were just pass throughs but it may share off hdmi.

Id stop using the ports and tape em off, have you tried the devices on your tower to verify it isnt the drive?
 
Could be just that its just not getting enough bandwidth honestly dont know
 
Older monitors were just pass throughs but it may share off hdmi.

Id stop using the ports and tape em off, have you tried the devices on your tower to verify it isnt the drive?
From memory early Dell monitors had a few USB ports but only certain ones were powered.
 
Just out of curiosity, are you by chance using 2.4GHz Wi-Fi to connect to the internet and it's a USB 3.0 hub? If so, you could get interference from the USB 3.0 part on the Wi-Fi signal, but that's about the only thing I can think of that would cause this.

Haha, I completely forgot about that one. I still can't believe that NONE of the USB-IF members caught that issue during the design and testing phase.
 
Interesting this is a surprise. I don't recall what monitor I owned, but, I did the same thing...used the monitor as my USB hub with whatever connected it and had noticeable input lag. So, I didn't use it anymore assuming that was normal. I mean, it has to go through another device in the chain which I simply imagined enough input lag to notice.
 
It really lagged up my computer when I used the USB hub on my Dell S3220DGF monitor. Programs would stutter, things would be slow to load, a lot of latency increase overall. It was very noticeable just browsing the web. Started when I connected the monitor's USB, and it stopped when I disconnected the USB. I have never connected it since.
 
Yes, it is weird, especially this part: "USB Type B", are you sure it is type B? Or did you mean type A?

On a bit more serious note: did you upgrade monitor's firmware or tried, if possible, a downgrade?
 
It really lagged up my computer when I used the USB hub on my Dell S3220DGF monitor. Programs would stutter, things would be slow to load, a lot of latency increase overall. It was very noticeable just browsing the web. Started when I connected the monitor's USB, and it stopped when I disconnected the USB. I have never connected it since.

Cheap controller with weak signal integrity.
 
Interesting this is a surprise. I don't recall what monitor I owned, but, I did the same thing...used the monitor as my USB hub with whatever connected it and had noticeable input lag. So, I didn't use it anymore assuming that was normal. I mean, it has to go through another device in the chain which I simply imagined enough input lag to notice.
I've used the hub on at least two of not three monitors without any issues whatsoever, so it should work fine...

Yes, it is weird, especially this part: "USB Type B", are you sure it is type B? Or did you mean type A?

On a bit more serious note: did you upgrade monitor's firmware or tried, if possible, a downgrade?
Nothing weird, type B is the correct port for the input to a monitor from a PC. It would seem you need to go and read up on the USB standard.
 
are we talking bout your lg 34 monitor ?

so it has:
USB-Hub Out2x USB-A 3.0
USB-Hub In1x USB-B 3.0


LG 34GK950F-B

quote:
After LG released a new firmware for this screen in early 2019 we wanted to take another look at it. We had confirmation from LG that the update was designed to improve a couple of things. Firstly it extended the supported Variable Refresh Rate (VRR) range from 55 - 144Hz to 48 - 144Hz, which gives a little bit of a boost. Secondly, and potentially more interesting was the news that it was designed to reduce the lag.

Screenshot_2020-04-05 LG 34GK950F Review - TFT Central.png

Updated v2 Firmware Tests February 2019


We were very pleased to see that the new firmware helped reduce all of the lag on this screen. We now had a signal processing lag of only ~0.2ms,
 
Last edited:
Shouldn't happen. I connect a usb type-A to type-B from MB to my Dell monitor, and from the monitor I have my keyboard and mouse plugged in, even with a usb drive plugged in from time to time. No lag. Worked fine for both windows and ubuntu.
 
I've used the hub on at least two of not three monitors without any issues whatsoever, so it should work fine...


Nothing weird, type B is the correct port for the input to a monitor from a PC. It would seem you need to go and read up on the USB standard.
To be honest first time i hear about type B as display input. I thought type C is the first use of usb for displays. The only use for type B i usually seen was for printers and similar devices, mini/micro type B for cameras, phones and other small devices. Now i'm curious what particular monitor model Easy Rhino owns, would like to look into specification to read more about it. Over 20 years in IT and i still learn new things about something what seems to be one of basic things like display input and output and usb standard. It is like with these motherboards having display port input somewhere in middle on their surface between cpu and gpu.
 
To be honest first time i hear about type B as display input. I thought type C is the first use of usb for displays. The only use for type B i usually seen was for printers and similar devices, mini/micro type B for cameras, phones and other small devices. Now i'm curious what particular monitor model Easy Rhino owns, would like to look into specification to read more about it. Over 20 years in IT and i still learn new things about something what seems to be one of basic things like display input and output and usb standard. It is like with these motherboards having display port input somewhere in middle on their surface between cpu and gpu.
It's not a display input, it's a USB hub built into the monitor that's causing the issue. I think you've misunderstood the OP's issue.
You're correct in that USB-C is the only USB connector that have official display signal support, although there have been some hack jobs using USB for all sorts of things, including PCIe signalling.
The stupid thing with USB-C is that if you want both the display signal and USB through the cable simultaneously, you end up with USB 2.0 data speeds...

The DP input on some ASRock boards is because they have some matching graphics cards, so you can run an internal cable from the DP out on the graphics card to the DP in on the motherboard to the Thunderbolt out on the rear of the board, all without any mess around the back of the PC.
 
It's not a display input, it's a USB hub built into the monitor that's causing the issue. I think you've misunderstood the OP's issue.
No, you mislead me with mentioning possibility of type B as display input. In general type B is rarely used in displays, most of the time it is just regular type A. Again, actually it is first time i hear about type B on a monitor, i googled now and i see mention of such monitors using type B on their hubs. I'm aware most of the time usb on displays are just hubs and in this case i also assumed it is a hub port and was still wondering if it would be type B as i've never before seen type B connection on a monitor.
 
Back
Top