My laptop has both USB2 and USB3 ports. I have a USB port extender
(powered) connected to the USB3 port, along with two USB3 hard drives. My
question is, when I want to transfer dat from one of those drives to the
other should I just leave them both connected to the port extender, or
whould I move one of them to the USB2 port to get the best transfer rate?

On 1/27/2023 10:10 PM, MajorLanGod wrote:
> My laptop has both USB2 and USB3 ports. I have a USB port extender
> (powered) connected to the USB3 port, along with two USB3 hard drives. My
> question is, when I want to transfer dat from one of those drives to the
> other should I just leave them both connected to the port extender, or
> whould I move one of them to the USB2 port to get the best transfer rate?
>

USB2 is half duplex (this sucks).

USB3 is full duplex. And this allows a device
to device transfer, on the same port, without much
of a penalty. Half of the drive interface, is busy on
each drive. One drive is reading. One drive is writing.
Both the Rx and Tx wires are fully occupied on the port
(the part on the left of my diagram) while the copy happens.

Tx +-----+
----| Drv | Source drive
Rx___/ +-----+

Tx___
\ +-----+
----| Drv | Destination drive
Rx +-----+

So if you take a USB3 port and put a hub on it, and
two drives plug into the hub, since each drive is only
using one of the two pairs of wires, the two transfers
do not conflict with one another. (Plus or minus a few
ACK packets.)

What is the suckiest part of a USB3 transfer ?

Why Windows of course :-/

Between Windows Defender, the Indexer,
the System Write Cache, they'll make a bloody mess. But we
cannot in this case, blame the USB3 wiring for the performance.
Perhaps an OS like Windows 2000 would do a better job of
file copying. I don't know if you can tell, but I haven't
been very happy with File Explorer.

You can try Robocopy, depending on what you're trying to do.
I expect the OS will still try to interfere with your work.

Paul

Paul wrote on 1/28/2023 12:25 AM:
> On 1/27/2023 10:10 PM, MajorLanGod wrote:
>>          My laptop has both USB2 and USB3 ports. I have a USB port
>> extender
>> (powered) connected to the USB3 port, along with two USB3 hard
>> drives. My
>> question is, when I want to transfer dat from one of those drives to the
>> other should I just leave them both connected to the port extender, or
>> whould I move one of them to the USB2 port to get the best transfer
>> rate?
>>
>
> USB2 is half duplex (this sucks).
>
> USB3 is full duplex. And this allows a device
> to device transfer, on the same port, without much
> of a penalty. Half of the drive interface, is busy on
> each drive. One drive is reading. One drive is writing.
> Both the Rx and Tx wires are fully occupied on the port
> (the part on the left of my diagram) while the copy happens.
>
>                          Tx +-----+
>                         ----| Drv |   Source drive
>                   Rx___/    +-----+
>
>                   Tx___
>                        \    +-----+
>                         ----| Drv |   Destination drive
>                          Rx +-----+
>
> So if you take a USB3 port and put a hub on it, and
> two drives plug into the hub, since each drive is only
> using one of the two pairs of wires, the two transfers
> do not conflict with one another. (Plus or minus a few
> ACK packets.)
>
> What is the suckiest part of a USB3 transfer ?
>
> Why Windows of course :-/
>
> Between Windows Defender, the Indexer,
> the System Write Cache, they'll make a bloody mess. But we
> cannot in this case, blame the USB3 wiring for the performance.
> Perhaps an OS like Windows 2000 would do a better job of
> file copying. I don't know if you can tell, but I haven't
> been very happy with File Explorer.
>
> You can try Robocopy, depending on what you're trying to do.
> I expect the OS will still try to interfere with your work.
>
>    Paul

I'll say in transferring between two HDDs, copying from USB2 to USB3
might be faster.

Reading and writing in the same USB3 port might have speed penalties.

Please try and tell us.

On 1/28/2023 6:07 AM, Mighty✅ Wannabe✅ wrote:
> Paul wrote on 1/28/2023 12:25 AM:
>> On 1/27/2023 10:10 PM, MajorLanGod wrote:
>>>          My laptop has both USB2 and USB3 ports. I have a USB port extender
>>> (powered) connected to the USB3 port, along with two USB3 hard drives. My
>>> question is, when I want to transfer dat from one of those drives to the
>>> other should I just leave them both connected to the port extender, or
>>> whould I move one of them to the USB2 port to get the best transfer rate?
>>>
>>
>> USB2 is half duplex (this sucks).
>>
>> USB3 is full duplex. And this allows a device
>> to device transfer, on the same port, without much
>> of a penalty. Half of the drive interface, is busy on
>> each drive. One drive is reading. One drive is writing.
>> Both the Rx and Tx wires are fully occupied on the port
>> (the part on the left of my diagram) while the copy happens.
>>
>>                          Tx +-----+
>>                         ----| Drv |   Source drive
>>                   Rx___/    +-----+
>>
>>                   Tx___
>>                        \    +-----+
>>                         ----| Drv |   Destination drive
>>                          Rx +-----+
>>
>> So if you take a USB3 port and put a hub on it, and
>> two drives plug into the hub, since each drive is only
>> using one of the two pairs of wires, the two transfers
>> do not conflict with one another. (Plus or minus a few
>> ACK packets.)
>>
>> What is the suckiest part of a USB3 transfer ?
>>
>> Why Windows of course :-/
>>
>> Between Windows Defender, the Indexer,
>> the System Write Cache, they'll make a bloody mess. But we
>> cannot in this case, blame the USB3 wiring for the performance.
>> Perhaps an OS like Windows 2000 would do a better job of
>> file copying. I don't know if you can tell, but I haven't
>> been very happy with File Explorer.
>>
>> You can try Robocopy, depending on what you're trying to do.
>> I expect the OS will still try to interfere with your work.
>>
>>    Paul
>
>
> I'll say in transferring between two HDDs, copying from USB2 to USB3 might be faster.
>
> Reading and writing in the same USB3 port might have speed penalties.
>
> Please try and tell us.

USB3 is full duplex. It can be going in BOTH directions
at the same time, at the full rate. If this port runs a hub with
two drives connected, one drive can be reading, one drive can be
writing, and that keeps the two wires pairs, fully busy.

TX+ \_____ 500MB/sec bus connection
TX- /
GND
RX+ \_____ Another 500MB/sec bus connection
RX- /

It's because there are two pairs of wires, you can support
two drives, one reading, one writing, without a major conflict.

There is still a need for ACK packets to signal that a write
is complete. There will be a bit of comms traffic, interspersed
with the deluge of data traffic.

USB uses high speed signalling at 5 Gigabit per second, to make 500MB/sec
of data. The encoding is something like 8B10B on lower rate
standards, and uses more efficient schemes on higher rate stuff.
The factor-of-10 between wire speed and bytes/sec, comes from
the "10" in the 8B10B. 8B10B encoding was invented for fiber optic
systems, eons ago, and has been reused many times on co0mputers
for wired interfaces. It has good edge content for clock recovery.
Notice that the USB interface has no clock-pair, like HDMI, DP,
DVI, PCI Express do.

Paul

=?UTF-8?B?TWlnaHR54pyFIFdhbm5hYmXinIU=?= <@.> wrote in
news:Nl7BL.3397549$f0c6.2227154@fx10.ams1:

> Paul wrote on 1/28/2023 12:25 AM:
>> On 1/27/2023 10:10 PM, MajorLanGod wrote:
>>>          My laptop has both USB2 and USB3 ports. I have a
>>> USB port extender
>>> (powered) connected to the USB3 port, along with two USB3 hard
>>> drives. My
>>> question is, when I want to transfer dat from one of those drives to
>>> the other should I just leave them both connected to the port
>>> extender, or whould I move one of them to the USB2 port to get the
>>> best transfer rate?
>>>
>>
>> USB2 is half duplex (this sucks).
>>
>> USB3 is full duplex. And this allows a device
>> to device transfer, on the same port, without much
>> of a penalty. Half of the drive interface, is busy on
>> each drive. One drive is reading. One drive is writing.
>> Both the Rx and Tx wires are fully occupied on the port
>> (the part on the left of my diagram) while the copy happens.
>>
>>                          Tx +-----+
>>                         ----| Drv |   Source
>> drive                   Rx___/    +-----+
>>
>>                   Tx___
>>                        \    +-----+
>>                         ----| Drv |  
>> Destination drive                          Rx
>> +-----+
>>
>> So if you take a USB3 port and put a hub on it, and
>> two drives plug into the hub, since each drive is only
>> using one of the two pairs of wires, the two transfers
>> do not conflict with one another. (Plus or minus a few
>> ACK packets.)
>>
>> What is the suckiest part of a USB3 transfer ?
>>
>> Why Windows of course :-/
>>
>> Between Windows Defender, the Indexer,
>> the System Write Cache, they'll make a bloody mess. But we
>> cannot in this case, blame the USB3 wiring for the performance.
>> Perhaps an OS like Windows 2000 would do a better job of
>> file copying. I don't know if you can tell, but I haven't
>> been very happy with File Explorer.
>>
>> You can try Robocopy, depending on what you're trying to do.
>> I expect the OS will still try to interfere with your work.
>>
>>    Paul
>
>
> I'll say in transferring between two HDDs, copying from USB2 to USB3
> might be faster.
>
> Reading and writing in the same USB3 port might have speed penalties.
>
> Please try and tell us.
>
>
>
>
Is there a specific program I should use instead of just 'drag & drop'
that might improve performance? I'm asking about native Win11 programs,
not third party.

Paul wrote on 1/28/2023 11:57 AM:
> On 1/28/2023 6:07 AM, Mighty✅ Wannabe✅ wrote:
>> Paul wrote on 1/28/2023 12:25 AM:
>>> On 1/27/2023 10:10 PM, MajorLanGod wrote:
>>>>          My laptop has both USB2 and USB3 ports. I have a USB port
>>>> extender
>>>> (powered) connected to the USB3 port, along with two USB3 hard
>>>> drives. My
>>>> question is, when I want to transfer dat from one of those drives
>>>> to the
>>>> other should I just leave them both connected to the port extender, or
>>>> whould I move one of them to the USB2 port to get the best transfer
>>>> rate?
>>>>
>>>
>>> USB2 is half duplex (this sucks).
>>>
>>> USB3 is full duplex. And this allows a device
>>> to device transfer, on the same port, without much
>>> of a penalty. Half of the drive interface, is busy on
>>> each drive. One drive is reading. One drive is writing.
>>> Both the Rx and Tx wires are fully occupied on the port
>>> (the part on the left of my diagram) while the copy happens.
>>>
>>>                          Tx +-----+
>>>                         ----| Drv |   Source drive
>>>                   Rx___/    +-----+
>>>
>>>                   Tx___
>>>                        \    +-----+
>>>                         ----| Drv |   Destination drive
>>>                          Rx +-----+
>>>
>>> So if you take a USB3 port and put a hub on it, and
>>> two drives plug into the hub, since each drive is only
>>> using one of the two pairs of wires, the two transfers
>>> do not conflict with one another. (Plus or minus a few
>>> ACK packets.)
>>>
>>> What is the suckiest part of a USB3 transfer ?
>>>
>>> Why Windows of course :-/
>>>
>>> Between Windows Defender, the Indexer,
>>> the System Write Cache, they'll make a bloody mess. But we
>>> cannot in this case, blame the USB3 wiring for the performance.
>>> Perhaps an OS like Windows 2000 would do a better job of
>>> file copying. I don't know if you can tell, but I haven't
>>> been very happy with File Explorer.
>>>
>>> You can try Robocopy, depending on what you're trying to do.
>>> I expect the OS will still try to interfere with your work.
>>>
>>>    Paul
>>
>>
>> I'll say in transferring between two HDDs, copying from USB2 to USB3
>> might be faster.
>>
>> Reading and writing in the same USB3 port might have speed penalties.
>>
>> Please try and tell us.
>
> USB3 is full duplex. It can be going in BOTH directions
> at the same time, at the full rate. If this port runs a hub with
> two drives connected, one drive can be reading, one drive can be
> writing, and that keeps the two wires pairs, fully busy.
>
>    TX+ \_____ 500MB/sec bus connection
>    TX- /
>    GND
>    RX+ \_____ Another 500MB/sec bus connection
>    RX- /
>
> It's because there are two pairs of wires, you can support
> two drives, one reading, one writing, without a major conflict.
>
> There is still a need for ACK packets to signal that a write
> is complete. There will be a bit of comms traffic, interspersed
> with the deluge of data traffic.
>
> USB uses high speed signalling at 5 Gigabit per second, to make 500MB/sec
> of data.

You might get 500MB/sec on SSD external drive, not a spinning HDD.

You should be laughing if you get 100MB/sec on HDD, much less if you use
flash thumb drive.

I don't have a USB 3 hub because I thought it was a good idea to
connected two USB drives to a hub.

> The encoding is something like 8B10B on lower rate
> standards, and uses more efficient schemes on higher rate stuff.
> The factor-of-10 between wire speed and bytes/sec, comes from
> the "10" in the 8B10B. 8B10B encoding was invented for fiber optic
> systems, eons ago, and has been reused many times on co0mputers
> for wired interfaces. It has good edge content for clock recovery.
> Notice that the USB interface has no clock-pair, like HDMI, DP,
> DVI, PCI Express do.
>
>    Paul
>
>

MajorLanGod wrote on 1/28/2023 1:53 PM:
> =?UTF-8?B?TWlnaHR54pyFIFdhbm5hYmXinIU=?= <@.> wrote in
> news:Nl7BL.3397549$f0c6.2227154@fx10.ams1:
>
>> Paul wrote on 1/28/2023 12:25 AM:
>>> On 1/27/2023 10:10 PM, MajorLanGod wrote:
>>>>          My laptop has both USB2 and USB3 ports. I have a
>>>> USB port extender
>>>> (powered) connected to the USB3 port, along with two USB3 hard
>>>> drives. My
>>>> question is, when I want to transfer dat from one of those drives to
>>>> the other should I just leave them both connected to the port
>>>> extender, or whould I move one of them to the USB2 port to get the
>>>> best transfer rate?
>>>>
>>> USB2 is half duplex (this sucks).
>>>
>>> USB3 is full duplex. And this allows a device
>>> to device transfer, on the same port, without much
>>> of a penalty. Half of the drive interface, is busy on
>>> each drive. One drive is reading. One drive is writing.
>>> Both the Rx and Tx wires are fully occupied on the port
>>> (the part on the left of my diagram) while the copy happens.
>>>
>>>                          Tx +-----+
>>>                         ----| Drv |   Source
>>> drive                   Rx___/    +-----+
>>>
>>>                   Tx___
>>>                        \    +-----+
>>>                         ----| Drv | Â
>>> Destination drive                          Rx
>>> +-----+
>>>
>>> So if you take a USB3 port and put a hub on it, and
>>> two drives plug into the hub, since each drive is only
>>> using one of the two pairs of wires, the two transfers
>>> do not conflict with one another. (Plus or minus a few
>>> ACK packets.)
>>>
>>> What is the suckiest part of a USB3 transfer ?
>>>
>>> Why Windows of course :-/
>>>
>>> Between Windows Defender, the Indexer,
>>> the System Write Cache, they'll make a bloody mess. But we
>>> cannot in this case, blame the USB3 wiring for the performance.
>>> Perhaps an OS like Windows 2000 would do a better job of
>>> file copying. I don't know if you can tell, but I haven't
>>> been very happy with File Explorer.
>>>
>>> You can try Robocopy, depending on what you're trying to do.
>>> I expect the OS will still try to interfere with your work.
>>>
>>>    Paul
>>
>> I'll say in transferring between two HDDs, copying from USB2 to USB3
>> might be faster.
>>
>> Reading and writing in the same USB3 port might have speed penalties.
>>
>> Please try and tell us.
>>
>>
>>
>>
> Is there a specific program I should use instead of just 'drag & drop'
> that might improve performance? I'm asking about native Win11 programs,
> not third party.
>

I can only think of 'drag & drop' or 'copy & paste' if you want native
to the OS.

I think you can managed about 40MB/s if you copy a HDD from USB 2 port
to USB 3 port.

I cannot try it myself for you now because my notebook has all USB 3 ports.

On 2023-01-28 20:30, Mighty✅ Wannabe✅ wrote:
> You should be laughing if you get 100MB/sec on HDD, much less if you use
> flash thumb drive.

I get 160.

--
Cheers, Carlos.

Carlos E.R. wrote on 1/28/2023 4:53 PM:
> On 2023-01-28 20:30, Mighty✅ Wannabe✅ wrote:
>> You should be laughing if you get 100MB/sec on HDD, much less if you
>> use flash thumb drive.
>
> I get 160.
>

I normally get 100MB/s. My external USB 3 HDD is High capacity (5TB) but
only 5400 rpm for backups.

I have some NVM2 M.2 PCle 2TB SSD on external case that can sustain
write speed of 950 MB/s but it is not good for backup drive because
sustained write operation can overheat and shorten the life. It will
throttle to reduce heat, to lower than 100MB/s (lower than HDD speed),
depending on the heat sink I clip onto chips.

Mighty??? Wannabe??? <@.> wrote:
> Carlos E.R. wrote on 1/28/2023 4:53 PM:
> > On 2023-01-28 20:30, Mighty??? Wannabe??? wrote:
> >> You should be laughing if you get 100MB/sec on HDD, much less if you
> >> use flash thumb drive.
> >
> > I get 160.
> >

> I normally get 100MB/s. My external USB 3 HDD is High capacity (5TB) but
> only 5400 rpm for backups.

> I have some NVM2 M.2 PCle 2TB SSD on external case that can sustain
> write speed of 950 MB/s but it is not good for backup drive because
> sustained write operation can overheat and shorten the life. It will
> throttle to reduce heat, to lower than 100MB/s (lower than HDD speed),
> depending on the heat sink I clip onto chips.

SSDs cost more too!
--
"I pray that out of his glorious riches he may strengthen you with power through his Spirit in your inner being." --Ephesians 3:16. Wandering Earth 1 was a meh, but will 2 B better?
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On 1/28/2023 1:53 PM, MajorLanGod wrote:

> Is there a specific program I should use instead of just 'drag & drop'
> that might improve performance? I'm asking about native Win11 programs,
> not third party.
>

Robocopy.

Originally written by a Microsoft employee for fun.

Now included *standard* as a part of the OS.

robocopy /? # voluminous help

robocopy D:\somedirectory E:\fluffy # It is basically a directory copier.
# But you can tell it to copy a single file.

robocopy D:\somedirectory E:\fluffy chunky.xls # Copies a single file, between those two directories.
# The file name will be preserved.

This is an example of a moderately complex command.

This copies the Y: partition onto the F: partition.
Anything that was on F: will be *destroyed*. The Mirror
option ensures that F: now looks like Y: and no file
merging is going on. When a user decodes a command someone
else wrote, they have to examine all the options, before
executing that command. Be careful with these!!! The /v is verbose.
I usually log my transfers, for later examination. If I notice
something was done incorrectly, I can go back and review.

cd /d C:\mylogfiles # Dump logfile in a known place.

robocopy Y:\ F:\ /mir /COPYALL /dcopy:t /XJ /r:3 /w:2 /zb /np /tee /v /log:robocopy_y_to_f.log

Paul