How Many USBs Can You Plug In At Once?

[TannerMcCoolman]

How many USB devices can be plugged into a PC at one time? It's a reasonable question, but the answer is more complicated than you might expect. We took 127 USB devices and plugged them in one by one until something broke. Then we took those same devices and reconfigured a few things to see if we can break it a different way. Just how broken do things get? Which limits get hit? How can you calculate YOUR maximum USB amount?

[MagickalMan]

What usb monitoring software were they using?

[TannerMcCoolman]

5 minutes ago, MagickalMan said:

What usb monitoring software were they using?

It's called USB Device Tree Viewer. It's a modified version of the USB Tree Viewer that comes with Windows Driver Development Kit. 

[TechPsychNova]

@MagickalMan Was able to barely see the application name from one of the screenshots shared in the video.
Looks like its called USB Device Tree Viewer. Found it online v3.8.7 - https://www.uwe-sieber.de/usbtreeview_e.html#download

 

Cheers.

[Gokul_P]

And here is my Amd chipset driver randomly crashing for plugging in a usb amazing.

[Stevis]

I don't think you guys could have gotten a better link for this video:
v=hiwaxlttWow
Hi, Wax! LTT: Wow!

[RandomLegoBrick]

someone had to do it lol

[Alffakisu]

Look at the URL of the video, how did you manage to pull that off or is it just some absolutely ungodly amount of rng 

[mariushm]

Guys, no, computers don't have a single USB host controller

 

For example, AMD processors have a usb host controller in them, along with pci-e controller  then the chipset also has one or two or maybe even more usb controllers.

With the x670 chipset where you have two chipsets connected together, you get even more usb controllers.

 

For example in my system  device manager shows two usb controllers

One is vendor id 1022 (AMD) , device ID 149C  Matisse USB 3.0 host controller https://devicehunt.com/view/type/pci/vendor/1022/device/149C

The other one is vendor id 1022 , device ID 43EE 500 Series Chipset USB 3.1 XHCI Controller   https://devicehunt.com/view/type/pci/vendor/1022/device/43EE

 

Also some motherboard makers resort to creating 4 or more USB 2 ports on the IO shield by hiding a USB hub chip there, so that can explain why you would not be able to plug as many hubs or devices in those usb 2 ports, because you already have a hub IC.

 

Some motherboards will have a 2A or 3A resettable fuse for every 2 usb 3 ports, or 2-4 usb 2.0 ports - so one of the 2-4 ports could draw up to 2A without any problems but if two consume a lot of power the protection could kick in.

[LMGcommunity]

1 minute ago, Alffakisu said:

Look at the URL of the video, how did you manage to pull that off or is it just some absolutely ungodly amount of rng 

RNGesus smiled upon us today

[Gokul_P]

27 minutes ago, Stevis said:

I don't think you guys could have gotten a better link for this video:
v=hiwaxlttWow
Hi, Wax! LTT: Wow!

There aren't words in url. This is millions to one. 

 

[LeapFrogMasterRace]

0 If you are using AM4

[Nystemy]

To be honest.
USB IF should amend their power standards a bit.

Would be nice if any USB port could specify its power delivery capabilities. Be it 5 volts 500 mA, 1 amp, 1.5 amps, or 2 amps that a USB type A port can handle fairly well.
To be fair, implementing the whole USB power delivery spec for this negotiation wouldn't be weird.

Sadly USB IF in their infinite wisdom removed 12 volts as a negotiable voltage from the power delivery spec... But 9 volts is still a thing. And with a simply boost converter motherboards could provide 24 or more volts as well. So reaching the USB-C maximum of 48 volts 5 Amps wouldn't be unrealistic, just think of all the devices one could power with over 200 watts. _{(imagine having to have a 6 or an 8 pin power cable going to a USB controller card just to keep it happy. And then it might only have 1 USB-C port.)}

However, I am still awaiting the day one can casually connect two computers over USB and transfer files that way. USB 3 sure does beat most people's networking capabilities by far. _{Though, I upgraded to 10 gig myself, so this has become somewhat needless for me at least...}

[Juest]

lol i have two korg nano midi controllers plugged to a usb 2 hub and its working just fine when the manufacturer says i should be using a external power, this usb 2 hub is pretty crappy and it seems to be broken because it randomly reconnects, randomly fails, and yet it still works fine here and there

very cool experiment guys

[Crunchy Dragon]

USB supports up to 127 devices, so I'm gonna guess at least 7.

[ImorallySourcedElectrons]

All hail the (usually) 8051-based USB host controller! But joking aside, it's also fun how some host controllers will actively detect certain screw-ups and adjust their own behaviour to still make the attached devices work. That's one of the reasons you can get away with some of those ridiculous minimalistic USB interface circuits.

[DJboutit]

I have 8 external hard drives and one usb flash drive hooked up to my computer one is a SSD drive running Windows 10 every works just fine. The External SSD is the only way I could get Windows 10 installed and working with UEFI Bios.

 

I have 4 drives in one of these 4 bay docking stations and the other 4 drives hooked up individually

 

Here are the specs on my computer

 

HP Victus

Ryzen 7 5700G

32GB 3200MHz

RX 6600 XT

500gb M.2 I am not able to use Since with configuration does not even see the drive now

500w power supply

 

I plan to get one 12TB external hd soon then down the road more for external hd for a total of 10 external hds

[crism]

What was the reason for using a PC for the shoot that was a different system than the one you did your testing on?

[Alvin853]

Why are you casually ignoring the fact that the software kept showing "USB 2.1" hubs? Can you explain what USB 2.1 is?

[ImorallySourcedElectrons]

5 hours ago, Alvin853 said:

Why are you casually ignoring the fact that the software kept showing "USB 2.1" hubs? Can you explain what USB 2.1 is?

No one knows what USB version numbering means, not even the standards body. 

[danwat1234]

Sooo That's why my ~1PiB Chia farm was so troublesome to set up. I thought device limit was 127 per controller with Depth of 5. But once i added 1 too many i would see drop outs and different on every power cycle. Seemed like a max of about 40 drives, 20 dual bays or so.  So I ended up buy a Febsmart 1-controlller and a 4-controller card so it has a total of 6 USB controllers on a Dell SFF box, 8th gen Intel. Yes, internal PC just has 1 controller. I guess Febsmart doesn't have super duper Endpoint support. 

I think all my connections is a 7-port powered hub and then connecting more 7-port hubs from 1 of the first four ports of that hub so 1+1(or2 if using port 5+ on 2nd deep hub) + the device, so 4 deep, not issue.

91 devices, most of which are dual-bays.  not sure how to get total tally of # of endpoints with that software. 

[darknessblade]

Its a shame Linus did not add/build the USB powered grill:

https://akibabara.com/aho/24/

[NadiaMayer]

3 hours ago, danwat1234 said:

Sooo That's why my ~1PiB Chia farm was so troublesome to set up. I thought device limit was 127 per controller with Depth of 5. But once i added 1 too many i would see drop outs and different on every power cycle. Seemed like a max of about 40 drives, 20 dual bays or so.  So I ended up buy a Febsmart 1-controlller and a 4-controller card so it has a total of 6 USB controllers on a Dell SFF box, 8th gen Intel. Yes, internal PC just has 1 controller. I guess Febsmart doesn't have super duper Endpoint support. 

I think all my connections is a 7-port powered hub and then connecting more 7-port hubs from 1 of the first four ports of that hub so 1+1(or2 if using port 5+ on 2nd deep hub) + the device, so 4 deep, not issue.

91 devices, most of which are dual-bays.  not sure how to get total tally of # of endpoints with that software. 

That fire hazard.

Either way crazy

[VinLAURiA]

Hot damn, it go.

 

I kinda wonder what would've happened if that "USB-inator" ran off of an AMD chip like the first PC you used. Might you have hit that 127-device limit after all? Or would that limit not have even mattered and the AMD chip just kept YOLO-ing it?

[nhand42]

19 hours ago, darknessblade said:

Its a shame Linus did not add/build the USB powered grill:

So that's what they did with the unsold inventory of AMD FX processors.