Sorry, but it’s a known issue: http://www.plugin-alliance.com/en/support.html
Noise and CPU issues in Cubase on Windows
There have been reports of problems from primarily Windows 7 users in Cubase 8.5. These can include audio glitches during playback, brief noise bursts, or host crash / hang.
We are working closely with Steinberg to track down the issue and provide a resolution. Until then, there are a few things you can try to mitigate the problems:
Troubleshoot by temporarily removing any connected USB flash drives from your system.
Try removing the VST3 version of your plugins and only use VST2; you can either do this by manually deleting them from the installation folder (usually ‘Program Files\Common Files\VST3\’), or deselecting the ‘VST3’ option when performing a clean install.
Use legacy versions of your plugins (pre-April 2015). You can obtain these by providing a list of required installers to Tech Support.
Update the drivers for your audio interface.
For users of antivirus software, try disabling real-time scanning.
Please note that some newer plugins will not be available as legacy versions.
If you continue to have issues, please contact Tech Support and be sure to provide as detailed information about your system as possible. The more in-depth information we have concerning your system, the more efficiently we can help solve this issue.