Biller wrote:

Win 7 Pro. Updated.

USB3 flash pen drive with 20G of data to copy.

Plugged into a USB3 (blue) port on Win 7 desktop.

Coping to a 8T NAS on my home LAN. Plenty of space on the NAS.

After One Day 11 Hours it says it still has 8 Hours left to complete copy.

Win 7 PC is wifi connected on 5GHz channel.

Router is AT&T wifi and internet connection 1Gbits.

NAS is CAT5 to Router.

Why so slow ?

Is the USB3 stick healthy ?

What you're looking for, is areas of the USB3 stick with
large downward spikes that almost touch the bottom of the
chart.

My USB3 setup on this machine is far, far, from optimal.
But I still get a rate comparable to some of my crusty hard
drives. I could likely get a better benchmark out of the
other machine. But at least you can see it doesn't
have any bad spots. I've lost two other USB3 sticks with
TLC flash inside, so failure is definitely an option.

https://i.postimg.cc/Hn0TVhsz/USB3-stick.gif

You might be coming close to losing that USB3 stick
(complete failure). Safety first. When they go, they
will likely go the same day you start having trouble.

*******

USB3 peripherals can emit broadly at 2.4GHz, smothering
low band Wifi. However, you report your gear is running
5GHz, and that is unaffected. The broad peak at 2.4GHz is
notched at 5GHz, so there's almost no noise there. The
5GHz Wifi isn't exactly at 5GHz, so you'd have to look
up the numbers to see whether the Wifi sits in the
notch.

If you can get HDTune to scan the stick (doesn't always
show up), that can help you decide what to do next. Considering
the circumstances, you can run HDTune right now, while the
transfer is still running, and get a good overall picture.
That's because the USB3 stick isn't running even remotely
close to the bus limit, so two things could easily read
from it at the same time.

If you were to let the transfer finish, then I'd want to
run a checksum program on the source and destination
file(s).

Paul