Drobo 5D connection puzzler

I have a Drobo 5D that I haven’t used for a few years, that I decided to revive. Testing it on my
old HP Pavilion 490 desktop, upgraded from Windows 7 to Windows 10 pro 1909.
I have some spare fairly new WD SATA disks (8 & 6 TB) in the Drobo to test it with.
On this desktop, the Drobo works - it goes thru its boot cycle, the disks show green …
but the performance is terrible. The dashboard won’t stay connected, and often doesn’t find
the Drobo at all. I did upgrade the dashboard and update the drobo firmware, this latter during
a period where the dashboard was staying connected.

Read/Write speed is typically around 10 MB/s altho some readings will get to 100 MB/s, more like what I expected (& what I would need, for the device to be usable).
Other USB 3 disks on this desktop have normal performance - over 100 MB/s transfer speeds.
I tried the Drobo on a Windows 8.1 laptop, and a different desktop & laptop both running Windows 10 1909 - no problems at all. Very good performance, > 100 MB/s, and no problems with the dashboard
staying connected to the Drobo. As far as I can tell all of these computers used intel chip sets for their USB interfaces but not sure what the differences are (or how to report them).
The Drobo used to perform very well on this desktop when it was running Windows 7 pro.
What can be done to fix this? Any ideas appreciated.

Just a check on the (assumed) USB connection with your Drobo - does your HP have, and did you connect it to a SS-port USB, over a standard USB port?

The HP 490 has 2 USB 3.0 ports, and the Drobo was connected to one of them.
They’re 3.0, not the later, faster 3.1 or 3.2

The Drobo has the same behavior on any of the USB 2.0 ports the HP 490 also has.