The speed of the VPS hosting depends on the selected VPS configuration. For example, the VPS 256 tariff is not intended for simultaneous launching of more than two MT4 trading platforms with operating expert advisors.
If this requirement is fulfilled, but the VPS hosting is still operating slowly, you should check and disable all unnecessary programs that influence the VPS. You can do it with the help of Task Manager, launched by pressing Ctrl + Alt + Delete.
The easiest way to improve the speed of the server is to upgrade your VPS tariff.