Since updating my MacPro 2009 (5,1 firmware) to High Sierra (all versions, now on 10.13.2), it generates thousands of threads per hour (about 5-10 thousand per hour). Before long I am running tens of thousands of threads and after about 50K or so my computer starts slowing down unbearably and I need to restart. I've tried starting up in safe mode and this does not help. I've tried a new account login and this does not help. Strange to me is that my other computers running High Sierra don't even have a Kernel_Task listed in Activity Monitor. Any help would be appreciated. If I do a clean install, I will never remember all that stuff I've installed which was running fine before High Sierra. I have a 1gb SSD, 48gb of ram and a GTX-980ti installed (all worked great on Sierra).