problem with asio performance

My writing English is not good but I can read and understand what you write.
I have a PC with 32GB RAM \Intel® Core™ i7-5820K CPU @ 3.30GHz 3.30 GHz \ win 8.1 \ 64-bit Operating system, x64-based procssor
DAW: Cubase 5.1.1 Soundcard: focusrite scarlett 18i20
My problem is when I load pr open some samples or plugins (for example “Abbey road plates stereo”) the VST Perfomance asio gauge gets full and breaks down and I can’t continue to work.
Can anyone help me? Please