Hi Chris ,
I loaded a version from may 2014 last night and experienced the same problems, i noticed that the driver version is the same as in current version for the 490EX; what i eventually did was to switch to a different USB port (also 3.0) and it was OK for a few hours until i experienced a small freeze problem but i just had to restart Artemis to resume imaging. So it was fine.
When i experienced real problems with the atrik 490ex, an occurrence of artemis for the atik 490 was running in background and i needed to disconnect and reconnect the camera to restart artemis, until the next problem.
I hope it will be ok with the other usb port.
Regards
Pascal