Hello! I have a problem with Samplitude Pro X4 (15.0.1.139)

I'm trying to put plug-ins from iZotope RX7 (VST2, 64bit) on objects or tracks, but they loading about 20-30 seconds per one plug-in. In the beginning I thought that plug-in isn't well, or installed with problems but than I tried open the same plug-in with Nuendo and Pro Tools. It's works better and loading more faster (1-2 second per plug-in) . What can it be and how is it fix?

Thank you for your answers!

Hardware pretty enough:

Windows 10 (64bit), Xeon CPU E3-1245v3 (3.40GHz); RAM 24Gb