Some people have reported that disabling hyperthreading causes Premiere Pro to be stable. You can also "set affinity" for the Premiere Pro process to a single CPU. Details are in the Microsoft Windows Help and Support.
I use Hyperthreading on my machine and almost never have a problem. There have been times when the machine becomes unstable and for me it has always been a corrupt workspace file. You might try selecting one of the default workspaces and modify to your liking then save it. that has been the problem for me so far
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