High speed ports on motherboard back-panel

[cst1992]

Why do modern motherboards have so many high-speed USB ports on the back panel nowadays? Is it just because they are connected directly to the motherboard - like side ports on a modern TV?

Note that I am only talking about the commonplace type-A ports here.

In the case of my current PC I have two 2.0s and four 3.0s for a total of 6. A lot of mainstream motherboards have a similar configuration - but with even higher speed USB 3.1/3.2 gen 1/2 ports.

Some of the motherboards I am looking at have 5 or more high-speed ports.


This doesn't make sense to me. For me the only high-speed thing you'd want to connect is a USB 3.x hard-drive/SSD and that has a cable of only about 50cm(20 inches) so I'd not want to connect that to the back panel.
In my current PC I only have my keyboard, mouse, printer and a bluetooth dongle connected, none of which require more than USB 2.0.

What am I missing here?

 

[Mussels]

You're missing that many devices actually need 3.0
Many modern mice and keyboards need the higher power or lower latency of USB 3.0 (RGB keyboards, 1000Hz gaming mice)
Modern wifi adaptors would be a laugh on 480Mb USB 2.0, even my 'old' AC1200 setup would be crippled
I dont even have a single USB port free... multiple external SSD's, wireless mice and headphone dongles (that do state they need USB 3.0, even if they often dont)
Even my monitor and speakers require USB 3.0 (monitor has a hub, speakers have a DAC)

Anything with a battery charges twice as fast on 3.0 as it does on 2.0 (assuming they follow the specs, many mobos have their tricks for higher charging on 2.0)

 

[cst1992]

Many modern mice and keyboards need the higher power or lower latency of USB 3.0 (RGB keyboards, 1000Hz gaming mice)

Hmm. I don't use those, so I never noticed.

Modern wifi adaptors would be a laugh on 480Mb USB 2.0, even my 'old' AC1200 setup would be crippled

True. Even for gigabit you need, well, gigabit.

Even my monitor and speakers require USB 3.0 (monitor has a hub, speakers have a DAC)

A DAC? They don't use the 3.5mm ports?(Again, I don't use high-end speakers or even speakers at all - I'm a headphone guy).

Anything with a battery charges twice as fast on 3.0 as it does on 2.0 (assuming they follow the specs, many mobos have their tricks for higher charging on 2.0)

Yeah, the red/yellow ports I've seen do that.
I have to try the battery thing out. How fast are you talking about? My current phone has a 3000mAh battery that recoups 1% of charge per minute on its dedicated charger. I don't know the wattage of that but the cable is rated for 25W.

 

[joemama]

Aren't your keyboard and mouse connected through USB?
For me, my keyboard and mouse take up 2, 1 for the monitor for software control, another 1 for my microphone. That adds up to 4, if you have a printer or high end speakers it could easily add up to 6, it really just depends on how many devices you are operating.

 

[Mussels]

Hmm. I don't use those, so I never noticed.

True. Even for gigabit you need, well, gigabit.

A DAC? They don't use the 3.5mm ports?(Again, I don't use high-end speakers or even speakers at all - I'm a headphone guy).

Yeah, the red/yellow ports I've seen do that.
I have to try the battery thing out. How fast are you talking about? My current phone has a 3000mAh battery that recoups 1% of charge per minute on its dedicated charger. I don't know the wattage of that but the cable is rated for 25W.

Logitech G560 - pure USB is an option (Feature i wanted, razer soundbars had annoying crackling issues on 3.5mm)

Phones go beyond the USB specs and require fancy chargers - USB 2.0 is 5W, USB 3.0 is just under 10W
Smartphones can blow way past that with various unique incompatible fast charge methods, so they'll simply never fast charge from a PC.

 

[Palindrome]

Counterquestion: why not?

In all seriousness though, it's been a thing for a long time, albeit it's evolved. In the past, you'd have PS2 ports for your mouse and keyboard, dedicated printer port, serial port, etc... USB simply allows you to plug in practically anything, and the increase in bandwidth for said ports is just technology improving and the need for higher bandwidth connectivity arising (both on the board and peripheral side). As mentioned above, WiFi dongles, external storage devices, etc. would be woefully crippled by older USB iterations, so having the flexibility that every (or if not every, most) USB port on your board can do high speed data transfer is very welcome imo.
This topic reminds me of an LTT video not too long ago where they tested a mobo from Asrock that had a dedicated USB chipset for certain ports to "reduce latency and improve performance". Turned out to be absolute bogus...

 

[cst1992]

Aren't your keyboard and mouse connected through USB?
For me, my keyboard and mouse take up 2, 1 for the monitor for software control, another 1 for my microphone. That adds up to 4, if you have a printer or high end speakers it could easily add up to 6, it really just depends on how many devices you are operating.

Agreed, but all these run on 2.0 fine.
As I said in another post, I don't use high-end peripherals(e.g. gaming mice) so I never came across any of them really needing a lot of bandwidth.

 

[Mussels]

Currently on my system:

USB 2.0:
Xbox receiver
Headset receiver
Mouse (charging)
Logi G560 speakers
Mic
Webcam (many modern ones require 3.0 for 4K)
UPS

USB 3.0 (but ofc, they all work on 2.0 to some extent)
RGB Keyboard (Power, usually works on 2.0)
Monitor (it has its own hub/software control)
Mousepad (I have RGB and wireless charging)
USB flash drives
USB SATA dongle (drive reading/cloning/fixing)
USB SATA SSD enclosure
USB NVME SSD enclosure


It's simply part of the design specs, and silly to go backwards. You'd be pissed if a PC had 12x USB 2.0 ports and 4x USB 3.2, and you needed 5...

 

[TheLostSwede]

Because most of them are an integral part of the chipset that the motherboard is built around?
All USB A ports are backwards compatible anyhow, so why does it matter?

 

[Ferrum Master]

What am I missing here?

Signal degradation, long traces, loss due to additional connectors, EMI interference.

I avoid USB3 front panel connectors like plague.

 

[Mussels]

Signal degradation, long traces, loss due to additional connectors, EMI interference.

I avoid USB3 front panel connectors like plague.

That's a good point, i often have issues with drives on front ports, that work fine on rear ports.

 

[Ferrum Master]

That's a good point, i often have issues with drives on front ports, that work fine on rear ports.

It is written in the USB3 implementation bulletins. USB3 has a adaptive feature, it has a budget overhead for slowing down if some crap cabling etc occurs to maintain signal integrity. Ever wondered why even USB speeds differ in between motherboards in reviews? That's because of the way it is routed.

I've used USB extensively in mobile phone and other device firmware flashing, considering these are in more than hundreds of thousand devices that has gone through my hands... some devices are more sensitive to cable lengths than other, but I am not willing to risk either way. Front panel can be used for non crucial things, like peripherals and some specific things like security keys, dongles... else... nope...

 

[TheLostSwede]

Signal degradation, long traces, loss due to additional connectors, EMI interference.

I avoid USB3 front panel connectors like plague.

Depends what you use them for. Plugging in USB thumb drives is perfectly fine, plugging in something with a 2 metre cable, not so much.

 

[Ferrum Master]

Depends what you use them for. Plugging in USB thumb drives is perfectly fine, plugging in something with a 2 metre cable, not so much.

I had some UHS-1 card readers(sandisk and Lexar was even UHS-II) that also worked unstable while importing RAW's from my camera. It just disconnects after few GB of data.

So I can't take it as 100% bulletproof. The distinctive feature could be - it is totally fine for USB2.0, for 3.0 there might be dragons ahead.

 

[TheLostSwede]

I had some UHS-1 card readers(sandisk and Lexar was even UHS-II) that also worked unstable while importing RAW's from my camera. It just disconnects after few GB of data.

So I can't take it as 100% bulletproof. The distinctive feature could be - it is totally fine for USB2.0, for 3.0 there might be dragons ahead.

Sounds like you might want to get a better internal cable in your case, as I have had zero problems using a USB 3.0 card reader from Kingston connected to my front ports and that has a metre long cable.

 

[elghinnarisa]

Depends on what segment your looking at, the cheaper you go the fewer high speed USB ports you find generally. In my case I chew up 4x 3.0 ports just for my VR setup, then SD/card reader and harddrive dock eats another two. Thats six 3.0 ports just like that, mouse and keyboard can go on anything but im already up to using 8 ports in total and thats just so I dont have to go around swapping them.
Then I have plenty of other stuff as well, game pad, race wheel, drawing pad, camera, phone, tablet etc. A lot of them do not need high speed USB, but its rather nice to make use of it for many things like the camera, phone, tablet etc. Just for faster transfer speeds.
And of course occasional USB stick or the like.

Generally throwing in an additional USB controller is not the most expensive thing to do so its no wonder they add those on the more expensive or mid-segment motherboards. But if your going cheap, low end OEM stuff which can quite often be mATX as well, you get what, four if your lucky? high speed ports that is, maybe even less depending on system. Take a peak at random OEM motherboards on ebay or the like and you will find that many of them don't have a lot of USB ports at all, even less high speed ones. Same goes for most cheaper ones, A520, B450, B550 of the cheaper kind as an example. Which generally have 4 high speed ports, one type C and perhaps two 2.0 ports.

 

[Ruru]

I have 4x 3.0 on the rear I/O on my mainboard and they're all in use (external HDD, Oculus Rift + 2x sensors). Could use more though 2.0 is fine on the other stuff (keyboard, mouse and a hub which has WLAN and bluetooth dongles). Then I have 2x 3.0 on the case which I'll use for 3.0 USB drives.

 

[ThaiTaffy]

My case only came with one usb 3.0 to header but one can't have to many usb ports on a pc especially since sff motherboards are limited so I'll be ordering a usb c and 4 usb 2.0 backpanel ports to headers and fit them in somewhere in the coming weeks just need to find someone with a Dremel I can borrow here.

 

[cvaldes]

A DAC? They don't use the 3.5mm ports?(Again, I don't use high-end speakers or even speakers at all - I'm a headphone guy).

3.5 mm audio jacks on consumer PCs typically provide an analog audio signal.

Audio DACs typically require some sort of USB connection to a PC for the digital audio signal whether it be something like a Cambridge Audio DacMagic 100 or the USB DAC dongle that comes with the Razer Blackshark V2 headphones.

Going back to the original topic of rear panel USB ports, like some others have commented I also find that high-speed USB drives work far more reliably with the back panel USB ports versus the front panel USB ports.

I'm fine with plugging a little USB thumbdrive into the front panel port for sneaker-netting smallish files but if I'm making 50-70 GB Steam game backups, I'll plug the SSD drive into the rear panel USB port.

The modern chipsets support the high-speed USB interfaces anyhow so it makes more sense to offer a high-speed port when possible because they're backwards compatible with older transfer standards like USB 2.0 or USB 1.1 anyhow.

And while a given USB device may not saturate the bandwidth of a high-speed USB 3.2 interface, some devices may benefit from the lower latency of the high-speed ports.

 

[newtekie1]

Many modern mice and keyboards need the higher power or lower latency of USB 3.0 (RGB keyboards, 1000Hz gaming mice)

I don't see how the latency would be affected with USB3.0. USB2.0 works at 1000Hz just as well as USB3.0. The charging, maybe, if the current is too high, but I don't even think that applies either to most PC peripherals.

Anything with a battery charges twice as fast on 3.0 as it does on 2.0 (assuming they follow the specs, many mobos have their tricks for higher charging on 2.0)

Not really. The USB3.0 port can provide the extra current, but that doesn't mean the device can use it. If you plug something in that is only designed to charge at 500ma, it's not going to charge twice as fast on a USB3.0 port. And most devices are just designed to charge at that rate because its easy for the manufacturer. It takes far less effort, and components, to just designed a circuit to charge at 500ma than to designed a circuit to detect how much current the port can provide and then charge at that rate. Usually things like cellphones and stuff detect the current capabilities of the port, but things like mice just charge at the flat 500ma no matter what.

 

[Mussels]

Depends what you use them for. Plugging in USB thumb drives is perfectly fine, plugging in something with a 2 metre cable, not so much.

USB drives is where i have the most problems on front USB 3 - even on quality brand cases
It's usually as the drives get older and connectors wear out, but the common theme is that they work on all rear ports but glitch out under load on front 3.0

I don't see how the latency would be affected with USB3.0. USB2.0 works at 1000Hz just as well as USB3.0. The charging, maybe, if the current is too high, but I don't even think that applies either to most PC peripherals.

Not really. The USB3.0 port can provide the extra current, but that doesn't mean the device can use it. If you plug something in that is only designed to charge at 500ma, it's not going to charge twice as fast on a USB3.0 port. And most devices are just designed to charge at that rate because its easy for the manufacturer. It takes far less effort, and components, to just designed a circuit to charge at 500ma than to designed a circuit to detect how much current the port can provide and then charge at that rate. Usually things like cellphones and stuff detect the current capabilities of the port, but things like mice just charge at the flat 500ma no matter what.

They may not need it at all, but they 'officially' require it as part of their requirements
Probably because of crap like dell when they dropped laptops to 250ma and not 500ma all those years ago on laptops

You are also correct that USB 3 doesnt force the higher charging rate - but many smartphones and ipads that are USB 2.0 data transfer, support USB 3.0's power draw somehow despite it being against spec - theres a reason they're pushing USB-C to have standard charging rates.

 

[FireFox]

i often have issues with drives on front ports,

Don't tell me that you still use the front ports
Joking
Joke aside, i don't remember when was the last time that i used a front port. i got into the bad habit of cutting the cables from the front USB ports, Headsets and Microphone, it doesn't matter how expensive
the case is, i don't use those ports and i don't need it, i just cut them.
9 USB ports on the back panel is enough.

 

[Ferrum Master]

i got into the bad habit of cutting the cables from the front USB ports

Same here, hate those wires.

I have made a PCB routing one USB2.0 Line to front panel and there resides a simple HUB IC with hidden TYPE C header for ADC/DAC taken from wired phone headphones, to reduce device cost, thus I have a USB2.0 front panel and audio using only one USB line going across the case while keeping all functionality and looks.

 

[TheLostSwede]

USB drives is where i have the most problems on front USB 3 - even on quality brand cases
It's usually as the drives get older and connectors wear out, but the common theme is that they work on all rear ports but glitch out under load on front 3.0

Weird, I've never had a problem.

 

[Mussels]

Weird, I've never had a problem.

I loaded movies onto USB's over and over and over and over for my dad, to watch on his TV. simple wear and tear on the contacts i assume.