The ProcessIdleTasks trick is bogus. It won't clear the memory or whatever
True it has nothing to do really do with memory. Using it will only cause most defrag programs to completely undo any "file placement optimizations" it's performed making it redundant to use. I personally disable it via Microsoft Tweak UI.
Also "defrag -b" is undocumented by Microsoft, yet it's all over third-party "tweak" sites as some "boot optimization," personally I've tried it before and I noticed no difference.