I assume you mean running 1 stick while inserted in hub? I can try that today and allow to run at same 200mhz as a control experiment. I will report later when I get back from work.

The Zombie doesn't occur right away.  I varies, It runs normal for a few hours sometimes other times it seems to happen within minutes, totally random. I check temp from time to time (37c-39c). So Thermal runaway may not be an issue.