USB Hubs Are Input Lag Monsters? 

TL;DW -- USB Hubs Are Input Lag Monsters? No.

Back this guy on Patreon so he can get a better high speed camera!

The gaming scene needs more people like you. Great video.

Googled this because I'm out of usb ports, did not expect to find such a well tested answer. new sub

You are really answering the questions humanity needs answers to

Conclusion: 6:24 it does not affect the input lag

Never even tought about this till you made this video

6:40 - That's a Dirty Bomb. If someone is interested.

Brilliant test, exactly the scenarios I was looking for! And the results are so surprisingly positive! Thanks for tackling this question the right way and absolving me of my latency concerns. Subbed!

Great video. I was curious about this for a while and it's really interesting that there's no disadvantage!

nice to see youre still trying to improve the content with new tests like the mouse movement, good job

Your test setup and experiments are beautiful! Thanks for sharing :)

I love how every website out there swears that usb hubs gives you a shit ton of input lag and you should never use one for gaming, but they provide no data.

thank you for this awesome test. i always hesitated to use my monitors usb hub for my input devices because of being worried that it might cause "problems", but now i have to rethink my cable management thanks to you!

U really went deep... Very deep. Give this man a nobel price for this research.

Thanks for taking the time to conduct and publish these test. I'm sure we've all seen hundreds of posts with anecdotes or theoretically arguments over whether hubs affects input lag. But it takes controlled testing to get a definitive answer. This makes me feel better as my keyboard, mouse and sound-card are connected through a KVM switch (acts like a hub but lets me switch between two systems). I guess I'll have to go back to blaming internet lag and bad hit-boxes when someone beats me in CS:GO.

Great video! (I was planning the very details of my new PC setup when this question came up.) I expected to only find the usual "guesswork / non technically founded" discussions, but your video really blew my mind. Physically _measuring_ and then _veryfiying_ the results is a very scientific approach, I really appreciate this :).

Thank you for yet another great test! I haven't been able to use one of my USB hub inputs because I feared I would get additional input delay, so I had to plug a larger connector in which blocked one of the inputs. Now I can swap that and use all of the inputs :)

Thanks for doing this video. Just thought of this question this morning when I was considering getting a USB switch to quickly swap my mouse and keyboard between my gaming computer and work laptop. Didn't want my work life to potentially slow my gamer reflexes!

This is surprisingly interesting. Keep up the good work and cheers from Finland.

man you have alot of patience for all these tests...

I'm glad to see someone doing this sort of testing, to get rid of these dumb myths for good.

Nice video, i was impressed with the way you came up to measure USB latency with high camera and rigging a LED to mouse.

You deserve so much more subs and views. So much work done in those videos! :D

I was not expecting this video to be so informative. I guess LTT has been lowering my expectations for tech videos. Good job!

Very good to know that an extension cable is completely fine to use without any additional lag.

So you completely dropped the 'niche' phrase in your outro. Love the confidence. Keep it up :)

Thank you so much!!! Thought about this so much as I need to switch computers but only have one set of mic, mouse and keyboard for my streams and recordings. This helps a lot mate!

Finally some good testing set up. Really appreciate it.

I couldn't find hard test results for this ANYWHERE! Thank you so much.

Great video. Curious why click latency isn't effected by hubs but sometimes double clicks can be registered because of hubs. I've experienced this several times and have read other cases of it happening online.

I came here hoping to find an excuse for why I'm getting my butt kicked in CoD...now I must look elsewhere

In theory, it's not surprising at all that the latency does not increase even during a bulk transfer, because that's the whole idea behind the USB polling scheme -- since the traffic is completely shaped by the host controller, it can bound the latency for interrupt-class endpoints and the bulk transfer cannot interfere. It's very nice to see that being confirmed in practice by testing, however! If anything, it might be interesting to test whether the latency is affected by having more devices on the same USB root hub, since that means more devices that need to be polled, which might affect the overall polling rate.

Thanks a lot! I was searching for this, your video is perfect for me.

I was curious about this topic and couldn't find extensive information on it. Thank you

Great Work, that was exactly what i wanted to know because i start running out of USB Ports for all of my Wireless Logitech Devices!

Hello! I was wondering if with the introduction of new technologies and possibilities you could do an updated video! Is there a lag input between using a usb c hub with an hdmi connection to the monitor when compared to simply using the hdmi port in the pc?

Well constructed and clear analysis, with a cool accent too! :) Thank you for doing this. Subbed.

Really useful, concise, well presented, thanks a lot for making this.

This is such a great video. Thanks for putting the time and effort to make this.

I never actually thought about it. I had a bit thought, about that distance to motherboard a bit longer when connecting mouse/keyboard to front panel instead of rear, but it is like 0.5 or less meters, what is like maybe 0.01ms delay. So, thanks for such informative video!

Amazing, Thorough and well explained as always. (Thumbs up!)

Fantastically in-depth, but to the point video. Thanks! I use a mac and PC on the 1 monitor and unfortuntely most monitors only have 1 port to connect to its internal hub so i'll be confidently be using a USB 3.0 switching hub!

Thanks I was wondering about hubs affecting latency. really happy to see someone tested it out

I genuinely think you are the best tech RU-vidr on the planet. You have answered all the tough gaming questions with objective test results on so many topics I have needed answers from. We all really appreciate your hard work.

This video answered and solved several of my problems: 1. Lack of USB ports 2. Cables too short 3. Bad cable management Thank you!

Great video. Quality is amazing ! Thank you for your efforts

7:08 wow that deagle is larger than the m16

I wish you could make some test with usb extanders/repeaters/usb-lan adapters with 15m or more for guys want to try to outsource pc from living room. You've done amazing job. Subscribed!

Thanks so much for this info. I was looking into using a USB switch to switch my kb / mouse between my linux laptop and a potential gaming pc. Great to know there's no disadvantage!

What an awesome video for exactly what I wanted to know, thank you!

Very informative video, and quite surprising results. Cheers!

Man, you Optimum Tech, and GN are honestly the best. This video is exactly what I was looking for. Well done!

Thnak you for your time investiment. This video is great!

In theory, just having more copper makes lag worse by some nanoseconds, but it's not even measurable outside margin of error preceptable

This is fantastic video. I thought I was the only one out there truly curious about this!

i do think about this, ive troubleshooting the hell out of it and think i got it under control, well done for shining a spotlight on this usb can be messy, cpu, power settings, network, windows 10, nvidia, theres, chipset, hard ware etc etc a long list

Amazingly clear answer and explanation of a commonly asked question. Thank you, sir. Your diagrams were exceptionally clear... I just finished the video. Amazingly concise and the results are somewhat surprising as you say. Webcams now connected to monitor to eliminate cable run. Thanks again.

Came here three years later, extremely useful video, thanks!

that's a really surprising result and trying to not be biased against Hubs for responsiveness is going to be hard!

This is a cool video. Wondering if there’s an update. I noticed if results had been on a line graph showing normalized data (perhaps a simple % increase/decrease) then there are a number of places where you said “no change” that was actually a 5% change. Perhaps you could argue that it’s negligible, but it’s not zero.

Wouldn't it be easier to just look at the Desktop Cursor (or Game Cursor) to see when it starts moving?

This is strange. I got a different result with my test using my MIDI keyboard and Audacity. I recorded myself tapping the drum pad while FL Studio played a sharp sound, and I looked at the waveform on the screen. I could measure the space between the peak of my tap to the beginning of the triggered sound. I found that connecting the keyboard through an unpowered USB 2.0 hub consistently added to the lag. I can't remember if it was 5 or 10 ms.

very informative keep it up m8

You earned yourself a sub! This nice, good to understand and accurate testing is what i personally prefer to some "5 min production" videos. Keep the great work up!

Great video! Also what game were you playing towards the end?

very usful video for the MisTer FPGA budget set ups that use USB hubs! Wonderful info that makes me comfortable with my build.

This is exactly i was looking for. Thanks a lot

Great work bro answered all my questions about using a USB hub. Thanks.

From the moment I saw the title, I was prepared to answer "no"....the reason: USB is a polling communication, with the controller as master (why you can't just connect 2 PCs with a simple USB cable). While it's communicating with a device, that is the only time the device can give back data (unlike ethernet where packets can come and go independently). So all actual communication is directly between USB controller and device. All that USB hubs do is identify to which port they have to make ELECTRICAL connection. If that would be delayed, USB controller would close the communication window and "disconnect" the device. The only delay a hub could do is the "repeating" of the electrical signal, but even that should be done shorter than the USB clock signal (I assume; even if longer, we are talking nano/micro-seconds, not milliseconds).

Awesome and informative video, as always!

Thanks for taking the time out of your day to make this awesome video.

Great testing methodology. Thanks.

Subscribed. Thanks bro! Well done.

Great video! A question: Can I assume all tests you made are comparable to playing with a USB Controller on the Nintendo Switch plugged in a USB hub?

Finally found someone covering a related topic! I was wondering if I introduce any sensor error or input latency while using an USB A adapter for USB c gaming mouse or keyboard. I pick them to have a 5 ms advantage, but if it's diminished by the adapter and not having a USB c port in my pc, it doesn't make sense of course. Thanks!

Excellent! Will plug my mouse and keyboard into my monitors USB hub then :D Should make cable management easier with a sit/stand desk!

Very well tested and explained. Resolved my mystery, thank you.

I have a powered USB 3.0 10 slot replicator. I was wondering if I should plug my Mouse/KB dongles directly into the PC or on the hub itself with other stuff. Good video.

Amazing work, liked and subscribed, thank you.

This video came in clutch. On the hunt for a usb hub for my laptop right now.

epic study man , thanks for answering the question that we always had

This definitely used to be more of an issue with USB devices stressing old CPUs more than their PCI or PS/2 equivalents. I used to avoid USB network devices and such like the plague, but now with the limited PCI-E lanes and multi-core on modern processors I do the opposite. lol how times have changed.

Bro I haven't watched the video yet but I just wanted to say that I literally just had this thought while on the toilet and immediately after that, I go on youtube and I find you with this video. God it's like you read people's minds or something. God bless you man you are doing life saving work.

Just in addition to the video - the only case I found where the USB hub was an issue for me was connecting my USB headset gave me some interference noise. Aside from that I concur that I have noticed no delay with my keyboard, mouse and controller connected via hub \

For sure, some unbranded OEM ones lag for me. Good test!

amazing video, helped me a lot. thanks

you could have chained a few hubs together and then get the delay per hub by dividing by the amount of hubs

Thanks for the great video! I was thinking about getting a USB hub and was wondering about this. Also, Dirty Bomb is a great game!

Okay but does that still apply with a wireless USB dongle mouse? Or would having less power to it affect it?

This makes me wonder about raw PS/2 mouse vs USB->PS/2 converted mouse vs raw USB mouse. I've heard that PS/2 has its benefits because it sends interrupts to the CPU but I've never looked into if it actually works.

This is great info, thanks!

Awesome video !!! Keep up good work sir !

very good video and this gave me the confidence to connect my mouse to usb 3.0 hub. Only improvement proposal would be testing longer cables. I have 3m long cable and I think that many are using also 5m long cables.

You're the man! Super informative.

Thanks so much for this. You just saved me loads of time.

Man you are the frikin BEST!!! I'm shocked and super happy with the outcome.

Very very very helpful ! Thank you

thank you man. Amazing work !

I mean there is a difference, it's within 3 or 4 percent, but it does seem that there is a difference between the hypothetical fastest and slowest instances. It would be interesting to see if this type of test could be automated to allow for a much larger sample size. Awesome channel by the way, nice to see an actual breakdown of this kind of thing rather than just seeing peoples opinions and hearsay