Issue when accessing USB Card Readers via USB Anywhere under heavy load

Our application is running on a virtualized environment (VMWare) on Windows Server 2008R2.
This application is mainly running on IIS but is also via a separate executable accessing card readers that contain smart cards.
These smart card readers are connected to a AnywhereUSB Device (14 ports), in our production environment 10 of such card readers are configured.
Given experience from the past is more than enough capacity to handled our requests.
Smart card readers are from Gemalto IDBridge CT40.
Used driver for these card readers is the latest version for this OS (64-bit, 24/4/2013 version
During periods of low number of requests on the application there are no issues, during periods of more heavy load a problem occurs regularly when trying to access the smart card during the execution of a transaction.

Are similar issues known with the AnywhereUSB device being used in combination with smartcard readers / smart cards?
What are possible causes of this kind of problem?
What could help to resolve these problems?

What firmware and driver is the AnywhereUSB using?

Firmware version is 1.81.1570
Driver version is

I’ve heard of other customers using these kinds of devices with AWUSBs and 10 sounds like a reasonable number.

If you look in Device Manager after the issue happens, are the smartcard devices still present like before? Is the AWUSB itself still connected (RealPort USB components in the USB section of Device Manager; related USB Port LEDs still on)?

You might want to see if ‘hard coding’ the AWUSB’s NIC and the related switch port to 100 Mb / Full Duplex makes any difference, unless that’s already done.

If that doesn’t help, I suggest creating a support case with Digi. Likely, there are traces (logs) that would need to be setup, to see what exactly is happening in the AWUSB driver and firmware around the time the issue happens, vs. when everything is working correctly.