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Mine goes ZOMBIE about once per day. Sometimes twice in one day, sometimes it runs for 2 days straight. Is it a defective unit or not? I use CGminer 4.9.0 with no options. Plugged directly into a USB port on my desktop PC.
is not the USB port version 3.0 [blue color inside]?
No. Good old 2.0. No one ever said USB 3.0. was a requirement.