USB 3.2 Gen 1 vs Gen 2 Mobo Connector Confusion

[Barryng]

My new ASUS Z490-A mobo has two USB 3.2 connectors (the third USB 2.0 connector will not be used). One is a recognizable blue 20 pin "USB 3.2 Gen 1 header" and the other is is a very different looking small rectangular "USB 3.2 Gen 2 Front Panel connector". Although both connectors are defined as USB 3.2, the blue 20 pin header is referred to as "Gen 1" and the other new small connector is referred to as "Gen 2". Do both support the same rate of data transfer or is the new smaller one designed for faster communication rates?

My new Corsair Air 540 case uses a standard blue header for the front panel USB 3.0 ports so, out of necessity, I plugged the case front panel USB 3.0 ports into the blue 20 pin "USB 3.2 Gen 1 header" on the mobo rather than the seemingly ASUS intended "USB 3.2 Gen 2 Front Panel connector". I want to use the new "USB 3.2 Gen 2 Front Panel connector" for two additional back panel USB 3.0 ports needing a blue 20 pin header. Obviously I need some sort of adapter to due this as I cannot find back panel add on USB ports compatible with this new stye mobo connector.

Amazon has a short adapter cable but the reviews strongly indicated these adapter cables do not work reliably. Any suggestions?

 

[trents]

Gen 2 is faster than Gen 1.

Your only option would seem to be get a case that supports Gen 2 USB unless, that is, someone comes up with a more functional adapter which may happen in time. A lot of cheap Chinese adapters physically accommodate USB pin outs but the diameter of the cable may be insufficient to support higher transfer rates or they are too long and too skinny. I've seen this with replacement USB 3.0 external hard drive cables. They work but at USB 2.0 speeds even though they have the blue USB 3.0 plastic insert.

 

[Barryng]

Thanks for the response. When I posted the message above I didn't know what I didn't know so, although suspicious, the USB 3.2 designation made me think they would both be the same communication rate standard. Obviously, I was wrong. Well, I since found a good article that allowed me to build a secret decoder ring that makes the various and multiple name changes for the different generations understandable. Here it is and I hope it proves useful to others.

USB 3.0 -> USB 3.1 Gen 1 -> USB 3.2 Gen 1, at 5 Gbps
USB 3.1 -> USB 3.1 Gen 2 -> USB 3.2 Gen 2, at 10 Gbps
USB 3.2 -> USB 3.2 Gen 2x2, at 20 Gbps

So, the blue 20 pin header connector ("USB 3.2 Gen 1 header") is good for two 5 Gbps channels and, in my case, will handle the two blue USB A connectors on the front panel.
The new smaller connector ("USB 3.2 Gen 2 Front Panel Connector") is good for one 20 Gbps connector when one becomes available to plug into this connector. I am assuming it will drive only one connector because the 20 Gbps communication rate requires two 10Gbps channels.

Hope this proves useful and thank you again for your response above.

 

[trents]

What you say makes sense to me. Yes, the nomenclature used by the standards committees for USB has left a mess. I think it's one of those things were early choices in naming conventions years ago have put limitations on being consistent down the road. But who can predict the directions technology will take. It has consistently defied us in that regard.

 

[Perplexer]

When talking about internal motherboard USB 3 connectors, the blue 20 pin (2x10 pin) connector is known as the USB 3.0 / 3.1 Gen 1 / 3.2 Gen 1 header. It connects two (10 pins for each) USB 3 Type-A connectors on the computer case front panel, givng each of them 5 Gbit speeds. This is why, at the moment, front panel Type-A USB 3 ports are always only 5 Gbit, even on the most expensive motherboards.

The other smaller USB 3.1 / USB 3.2 header (black) first appeared on ASUS motherboards and is known as a "Key-A" header (sometimes refered to as "Type-E"). It also has 20 pins, but is meant for one USB Type-C front panel port or one USB 3 Type-A front panel port (not sure if any case manufacturer uses this last implementation currently). This one does not split into two connectors on the front so it dedicates all 20 pins to one connector (USB Type-C). This means that this connector can then offer speeds of 20 Gbit, but also 10 Gbit or 5 Gbit, depending on what chip it is "sitting on" on the motherboard. Cheaper motherboards will have this header and advertise it as "USB 3.2 Gen 1 (5 Gbit) front panel Type-C connector". More expensive boards with more capable USB 3.2 controllers will advertise this header as "USB 3.2 Gen 2 (10 Gbit) front panel Type-C connector". If your computer case does not have a front USB Type-C connector, you can buy a USB Type-C bracket that mounts at the back of your case and plugs into this "Key-A" USB 3.1/3.2 header on the motherboard.

True USB 3.2 Gen 2x2 (20 Gbit) USB Type-C connectors are currently only available on the BACK I/O of some motherboards.

There is also a specification for a 20-pin "Key-B" header which is physically / visually smiliar, but is supposed to support two Type-A connectors/plugs on the front panel. It is meant to replace those big old blue 20-pin USB 3.0 headers, but I don't believe any motherboard manufacturer uses these yet (or maybe they do on some small boards where space is at a premium). These "Key-B" headers (and the corresponding plugs) would likely be white in color.

And there is also a specification for a 40-pin header for 2 Type-C / 1 Type-C + 1 Type-A / 2 Type-A front panel ports. This one also probably doesn't exist on any board yet.

 

[SPL Tech]

These USB standards are silly. There is not a single device out there that can even fully saturate USB 3.0, let alone any of the newer standards. It's pointless tech at this point.

 

[EarthDog]

These USB standards are silly. There is not a single device out there that can even fully saturate USB 3.0, let alone any of the newer standards. It's pointless tech at this point.

a single sata based ssd comes close already at 550 MB /s (remember, overhead so 625 MB isn't theoretical). Throw an nvme m.2 on there and its blown out of the water. Those need 3.2 gen 2x2 (20 Gbps). But there are plenty of nvme based external storage options that can saturate USB 3.0 speeds.

 

[SPL Tech]

a single sata based ssd comes close already at 550 MB /s (remember, overhead so 625 MB isn't theoretical). Throw an nvme m.2 on there and its blown out of the water. Those need 3.2 gen 2x2 (20 Gbps). But there are plenty of nvme based external storage options that can saturate USB 3.0 speeds.

lol who runs an m.2 SSD over USB? Anyone trying to run one of those over USB clearly isint that interested in performance. You'd install it internally for that. Plus the USB bus has latency that doesent exist on the PCI-E bus so for more reason than one running an m.2 SSD over USB is a silly idea if you actually care about performance.

 

[Woomack]

lol who runs an m.2 SSD over USB? Anyone trying to run one of those over USB clearly isint that interested in performance. You'd install it internally for that. Plus the USB bus has latency that doesent exist on the PCI-E bus so for more reason than one running an m.2 SSD over USB is a silly idea if you actually care about performance.

I'm using two M.2 PCIe with USB 3.2 gen2x1 SSD which are pretty much going up to the max bus bandwidth so ~1.05-1.09GB/s, depends on the motherboard.
Here you have CDM made on Patriot PXD on ASUS laptop:


These results are about the same as on internal M.2 PCIe 3.0 x2 SSD. There are only few motherboards with USB 3.2 G2x2 ports and also barely any drives that run faster on USB ports.

 

[EarthDog]

lol who runs an m.2 SSD over USB? Anyone trying to run one of those over USB clearly isint that interested in performance. You'd install it internally for that. Plus the USB bus has latency that doesent exist on the PCI-E bus so for more reason than one running an m.2 SSD over USB is a silly idea if you actually care about performance.

Me... I've moved from a fast USB stick to external USB based NVMe storage. Creatives that need to work on large files too? What about external ssd storage in RAID5? That will do it. You also can't run a monitor with even 20 Gbps so Thunderbolt @ 40 Gbps using a type-c is there too (though that isn't usb except for the connector). Rareity wasn't a talking point... your point was "no devices" can saturate USB 3.0, remember.

 

[zcyclcras]

Perplexer, thanks for these details, I have been scratching my head trying to figure out the USB naming mess. One question that hopefully you or others might be able to answer, I have a case (Fractal Meshify S2) with a front panel USB 3.1 Gen 2 aka USB 3.2 Gen 2 USB-C Port. My ASUS Maximus XIII Hero MB has a USB 3.2 Gen 2x2 Header. If I connect the Front Panel to this Header, will I get 3.2 Gen 2x2 20Gbs speed or will it downgrade to 3.2 Gen 2 10Gbs speed? In other words, does the header determine what speed you get or does the port/cable determine it?

 

[EarthDog]

I don't believe that Z170 based board has a USB 3.2 Gen 2x2 header (It doesn't have a port on the rear IO...). I believe it has 2x USB 3.2 Gen1 headers that go to the front panel. You'd need a 3.2 Gen2x2 USB Type-C header to go to the front panel AFAIK...

....that said, the Asus website doesn't have a specs page for that board so I can only confirm by looking at the board itself.

 

[Blaylock]

You will get USB 3.2 Gen 2 Speeds (10GB/s). To get the full speed of USB 3.2 Gen 2x2 the connector, Motherboard, and device plugged in needs to support the faster 20GB/s speed.

 

[zcyclcras]

I don't believe that Z170 based board has a USB 3.2 Gen 2x2 header (It doesn't have a port on the rear IO...). I believe it has 2x USB 3.2 Gen1 headers that go to the front panel. You'd need a 3.2 Gen2x2 USB Type-C header to go to the front panel AFAIK...

....that said, the Asus website does have a specs page for that board so I can only confirm by looking at the board itself.

I left the ROG from the name out by mistake, I have the https://rog.asus.com/us/motherboards/rog-maximus/rog-maximus-xiii-hero-model

It is a z590 board

 

[EarthDog]

Nope (they are both ROG)... it was me. I looked up VIII, not XIII, lol.. my fault!

Blaylock nailed it.

You will get USB 3.2 Gen 2 Speeds (10GB/s). To get the full speed of USB 3.2 Gen 2x2 the connector, Motherboard, and device plugged in needs to support the faster 20GB/s speed.

 

[Perplexer]

Perplexer, thanks for these details, I have been scratching my head trying to figure out the USB naming mess. One question that hopefully you or others might be able to answer, I have a case (Fractal Meshify S2) with a front panel USB 3.1 Gen 2 aka USB 3.2 Gen 2 USB-C Port. My ASUS Maximus XIII Hero MB has a USB 3.2 Gen 2x2 Header. If I connect the Front Panel to this Header, will I get 3.2 Gen 2x2 20Gbs speed or will it downgrade to 3.2 Gen 2 10Gbs speed? In other words, does the header determine what speed you get or does the port/cable determine it?

Looks like top of the range motherboards now come with USB 3.2 Gen 2x2 on-board controllers / headers. So yes, you will get 20 Gbit speed on that USB Type-C connector on the front panel. The reason specs for that case say USB 3.1 Gen 2 is because they were apparently written before USB 3.2 spec was out. USB 3.2 introduces the Gen 2x2 transfer mode so if a Gen 2x2 header is available, that's what the front Type-C port will work at. The header (or more precisely the underlying controller) determines the speed. Mobo specs say Gen 2x2 so ASUS apparently used a Gen 2x2 capable controller chip so that's what you'll have on the front via that header.

 

[Blaylock]

Perplexer you may be correct. There are plenty of cases currently on the market that are still labeled with the USB 3.1 system. Even the Fractal website for the Fractal Meshify S2 is called out as "Front ports: 1 x USB 3.1 Gen 2 Type-C, 2 x USB 3.0, Audio I/O" This does not guarantee USB 3.2 Gen 2x2 speeds though. Do you have evidence to support your claims that the Meshify S2 is actually a 3.2 Gen 2x2 cable?

 

[Perplexer]

Cable is the same. USB 3.2 Gen 2x2 higher bandwidth is implemented over existing wires. As long as it is a Type-C connector, it will work in Gen 2x2 mode if it is connected to a Gen 2x2 header.

 

[Blaylock]

This article contradicts what you are saying. I'm certainly not an expert on this which is why I'm posting links.

https://www.google.com/amp/s/www.cn...-sense-of-current-and-confusing-usb-standard/

TL;DR -

All USB 3.2 Gen 2x2 products use the Type-C connector, but not all USB-C ports are USB 3.2 Gen 2x2. A USB-C port can be either 20Gbps USB 3.2 Gen 2x2 or 10Gbps USB 3.2 Gen 2. A USB Type-A port can be 10Gbps USB 3.2 Gen 2, 5Gbps 3.2 Gen 1 or even USB 2.0. USB 4 will clear up this confusion next year, but until then you'll need to read the fine print on products to ensure you're getting the expected USB 3.2 connection between your devices.

 

[dfonda]

All these posts and we still have not talked about what is important to some...How much power delivery? I needed that USB-C on the front of my case to fast charge a phone (It does). Not my laptop tho it charges, but not fast.

Just an average use, may find that more important than data speed. I personally move almost everything over Wifi or 5G.

Just to add a further layer to the USB specs...