USB 3.1 Gen 2 Type A to Type C adapter performance

gbellman

Trash Compacter
Original poster
Nov 7, 2019
53
11
Hi, I have a stupid question to ask. For mobo with native USB 3.1 gen 2 Type A (ASUS B450i & Aorus B450i), if I use adapter to convert it to Type C, will it perform same as a native USB 3.1 gen 2 Type C?

Assuming the adapter is not a cheapo thrash. Because I know that Type A only has 4 or 5 contacts, but Type C has 24 contacts, not sure with adapter how will it impact the performance, or there won’t be any impact at all.

Thanks ?
 

payo36

Caliper Novice
May 1, 2019
29
38
www.minicomputers.net
I tested it with my external NVME drive, it comes with both Type A to Type C and Type C to Type C cables. Type A gives the same speed as Type C as long as the port is 3.1 gen 2, but if I plugged into Get 1 port, the drive speed is reduced by half.
 

gbellman

Trash Compacter
Original poster
Nov 7, 2019
53
11
I tested it with my external NVME drive, it comes with both Type A to Type C and Type C to Type C cables. Type A gives the same speed as Type C as long as the port is 3.1 gen 2, but if I plugged into Get 1 port, the drive speed is reduced by half.
That means the speed is the same as long as the adapter is not shitty and both are 3.1 gen 2.

How about the power delivery?
 

payo36

Caliper Novice
May 1, 2019
29
38
www.minicomputers.net
Usually it'll max out at 900mA for USB A, somewhere around 5W. For USB C, it's 15W (on my ASUS board) If you over load it, there'll be a message pop up in Windows notification area.
 

gbellman

Trash Compacter
Original poster
Nov 7, 2019
53
11
Usually it'll max out at 900mA for USB A, somewhere around 5W. For USB C, it's 15W (on my ASUS board) If you over load it, there'll be a message pop up in Windows notification area.
Meaning there’ll be compromise when using adapter compare to native usb type c
 

Kilrah

SFF Lingo Aficionado
Feb 20, 2017
128
112
Only if the device you plug does need that much power (most won't) or features that are specific to USB-C like the DisplayPort mode.
 

gbellman

Trash Compacter
Original poster
Nov 7, 2019
53
11
Only if the device you plug does need that much power (most won't) or features that are specific to USB-C like the DisplayPort mode.
You mean other than the device required higher power and dp over type c, it’ll be the same for type a vs type a—>type c (using adapter)?
 

Quango

SFF Lingo Aficionado
Apr 6, 2019
102
34
... features that are specific to USB-C like the DisplayPort mode.
You think video output does not work via such an USB-A to -C Gen 2 cable or adapter?
(like this one
)

I have a brand new Asus ZenBook 14 UX434FAC with Comet Lake CPU that offers both USB-A and USB-C with 3.1 Gen 2, but it is hard to find out what they actually support compared to Thunderbolt, and also a pain to find compatible hubs and devices.
 
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gbellman

Trash Compacter
Original poster
Nov 7, 2019
53
11
You think video output does not work via such an USB-A to -C Gen 2 cable or adapter?
(like this one
)

I have a brand new Asus ZenBook 14 UX434FAC with Comet Lake CPU that offers both USB-A and USB-C with 3.1 Gen 2, but it is hard to find out what they actually support compared to Thunderbolt, and also a pain to find compatible hubs and devices.
Nop, my main concern is the speed and power because it’s mainly USB 3.1 Gen 2 Type A on few B450 itx, which doesn’t carry DP over Type A/Type C
 
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Quango

SFF Lingo Aficionado
Apr 6, 2019
102
34
Thanks, sorry if I didn’t clear enough. My question is, if using adapter, will the transfer speed and power delivered thru the Type C become lower?
Your question was perfectly clear but I have my own specific interests regarding Gen. 2 stuff, since that sits in the shadow of thunderbolt with half of its speed. Like Asus gives no specifics beyond "Gen 2." which keeps me wondering until I my Gen. 2 orders arrive.

Regarding speed an power with an adapter, I think with dedicated Gen. 2 adapters and cables like the following there should be no loss.
 

gbellman

Trash Compacter
Original poster
Nov 7, 2019
53
11
Your question was perfectly clear but I have my own specific interests regarding Gen. 2 stuff, since that sits in the shadow of thunderbolt with half of its speed. Like Asus gives no specifics beyond "Gen 2." which keeps me wondering until I my Gen. 2 orders arrive.

Regarding speed an power with an adapter, I think with dedicated Gen. 2 adapters and cables like the following there should be no loss.
How about adapter (not full length cable)? I think should be no loss also as long as it is specified by the manufacturer as Gen 2 SuperSpeed+
 

Quango

SFF Lingo Aficionado
Apr 6, 2019
102
34
How about adapter (not full length cable)? I think should be no loss also as long as it is specified by the manufacturer as Gen 2 SuperSpeed+
Now I've received the aceyoon adapter I linked to in post #8. It has printed "Max 5V" on it.

Also I've found out that my ZenBook 14 does not support alternative DisplayPort via USB-C Gen.2 at all, despite the i7-10510U SoC natively supporting Thunderbolt. Bummer. :(
 

gbellman

Trash Compacter
Original poster
Nov 7, 2019
53
11
Now I've received the aceyoon adapter I linked to in post #8. It has printed "Max 5V" on it.

Also I've found out that my ZenBook 14 does not support alternative DisplayPort via USB-C Gen.2 at all, despite the i7-10510U SoC natively supporting Thunderbolt. Bummer. :(
Meaning your adapter does not come with PD3.0 (which can supply max 20v).

AFAIK thunderbolt is different from type c, although the external look is identical, the internal structure is different, but some of it does support both thunderbolt & type c.

Too bad to hear that, perhaps you should rant at ASUS why they did that ?
 

gbellman

Trash Compacter
Original poster
Nov 7, 2019
53
11
Also I have another question, if both my mobo and device is Gen 2 (10Gbps), and I use Gen 1 (5Gbps) to connect both, will I get the full speed of Gen 2? Been Googling these few days and can't find the definite answer because there is no comparison of pinouts of the 2 gen, and also not sure if wiring/internal structure of these 2 are same or not
 

chx

Master of Cramming
May 18, 2016
547
281
Also I have another question, if both my mobo and device is Gen 2 (10Gbps), and I use Gen 1 (5Gbps) to connect both, will I get the full speed of Gen 2? Been Googling these few days and can't find the definite answer because there is no comparison of pinouts of the 2 gen, and also not sure if wiring/internal structure of these 2 are same or not
/r/usbchardware mod here, somewhat a walking USB C compendium

The reason a USB C-C cable can only do 5gbps is typically because it's longer than what the standard allows for 10gbps, so no, you won't get 10gbps over it. And both Gen 1 and 2 cables have an eMarker so you can't fudge this. The only way out is to get an active cable like what I posted yesterday:
 
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gbellman

Trash Compacter
Original poster
Nov 7, 2019
53
11
/r/usbchardware mod here, somewhat a walking USB C compendium

The reason a USB C-C cable can only do 5gbps is typically because it's longer than what the standard allows for 10gbps, so no, you won't get 10gbps over it. And both Gen 1 and 2 cables have an eMarker so you can't fudge this. The only way out is to get an active cable like what I posted yesterday:

Then how about Type A? Same also? Only Gen 2 cable can achieve the full speed of 10Gbps
 

Kilrah

SFF Lingo Aficionado
Feb 20, 2017
128
112
There is no specific cable for Gen2.
You will likely find cables that are "guaranteed to work at gen2 speeds" but that doesn't mean that an old good quality cable won't be able to do it. Some crappy ones might not.
 
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Valantar

Shrink Ray Wielder
Jan 20, 2018
2,201
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You think video output does not work via such an USB-A to -C Gen 2 cable or adapter?
(like this one
It definitely won't, as alt modes (such as DP alt mode) are specific to USB-C and there is no way of carrying this signal through a type-A connector. The required wires simply aren't there.

For type-C cables, there are two sets each of RX and TX differential pairs in the connector/cable for high speed signalling, which for G1 modes are fed through a multiplexer depending on the direction the cable is inserted so that the signal works regardless of how the plug is inserted (i.e. only one pair of each is used at a time). Nothing changes for G2 except the signalling rate. For G2x2, all pairs are used simultaneously, effectively doubling the lane count. This means USB 3.2G2x2 (ugh) is incompatible with type-A connectors.


The changes in the signalling are also the reason for G2 cables being shorter, as the more complex signal degrades faster and is more susceptible to interference


Edit: To clarify, (DP and similar) alt mode signals are sent through the TX/RX high speed data lanes in the type-C cable that are left unused by G1/G2 muxing. As these lanes don't exist on the type-A connector it is entirely unable to transmit these signals. This also means that 3.2G2x2 is incompatible with alt mode, meaning one has to pick either double lane count for higher data speeds or alt mode for other things.



Also I have another question, if both my mobo and device is Gen 2 (10Gbps), and I use Gen 1 (5Gbps) to connect both, will I get the full speed of Gen 2? Been Googling these few days and can't find the definite answer because there is no comparison of pinouts of the 2 gen, and also not sure if wiring/internal structure of these 2 are same or not
There is no change in the pinout between G1 and G2, only changes in the signalling. 8-pin Type A 3.0/3.1G1/3.2G2 has the required TX and RX pairs to transmit this same signal. Edit: As such this means the transfer speed comes down to the cable's ability to maintain signal integrity. For G2, that limit is rather short due to the complexity of the signal. Wiring is otherwise identical.

Edit(s): see above.
 
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