X300 Deskmini slow USB transfers

Hi all,

First time poster

Anywho, I have been trying to re-arrange my video's on to some WD 5tb external drives. When I run CrystalDiskMark I get 120 MB a sec average scores. But when transfering from one drive to another usually have transfers in the 15 MB range. Changed "policies" (yes, running windoz) to "better performance" and other minor fixes I found on the net to no avail. Then saw suggestion to install latest usb driver. Didn't find a usb driver on Asrock site so downloaded AMD chipset driver ver:2.05.04.352 and installed it. And, yes siree bob, I was getting 115 MB. That was last night. This morning after re-boot I'm back to 15 MB/sec.

I have a WD passport plugged in the back 3.0 port transfering to a WD Easystore in the front 3.0 port. No other peripherals or hubs attached.

I believe I have eliminated all other possible suspects either Windoze or the chipset.

Any thoughts would be appreciated.
Thanks in advance for your help

X300 DeskMini
Windows 10 Home 20H2
4650G
16 GB mem
ADATA SX8200PNP 1GB
WD My Passport 5TB
WD EasyStore 5TB

MackenK wrote: I have a WD passport plugged in the back 3.0 port transfering to a WD Easystore in the front 3.0 port.

Please lookup the exact model of harddisk you are writing to whether it is a convential (CMR) or shingled (SMR) type of harddisk. High capacity disks are usually SMR today.

Writing several GBs to a SMR harddisk is at first very fast, but then they slow down significantly when their inbound cache is full. This is normal behaviour for SMR type harddisks and has nothing to do with the host platform.