srtsp64.sys cpu usage high

Hi expert

SEP 12.1.2100 run in Win2k8 r2.

I found System Process usage over 25%.

My VM has 4vcpu so system process using 100% 1 of CPU(CPU1).

I use Process Explorer, srtspx64.exe using cpu.

Could you tell me what is srtspx64 and why srtspx64 using CPU high?

Thank you

Hiro