izotope very slow

i am using izotope a lot to master tracks. All of a sudden izotope has become very slow on my pc. I have no idea what happenend. Can anyone suggest what i can check? Loading an izotope vst(64 bit) takes 15 seconds or so CPU usage is at 3% when the vst is loading. Reaper itself also responds very sluggish when playing a song Rescanning plugins folder is also very slow My pc is I7 with 32GB ram and windows 10 64 bit

Are you running the latest versions of Reaper and the Izotope plugs?

yes, 5.4 and 7.01 Rendering used to be at 13x speed, now at 2,9 speed

i am rendering lots of 1 hour files. It starts slowly at 2.9x realtime, and after some time it goes up to 7x, and then down again While cpu usage is only 2-3% Ill see what i can find about off and online use

would it be easier to go back to an earlier version? i think this happenend after i upgraded

very strange, rendering with isotope active goes at speeds of 2-3x real time When i play music though on my pc, f.i. through foobar, it speeds up to 17x real time?? What could cause that?