What affects the speed of VDS in the first place?

Question

ISPmanager

There are sites (on Wordpress and on php without CMS). On Timeweb'e work fast enough.
We are transferring (so far we are making a copy of these sites) to VDS ihor.
VDS parameters at the moment: 2 CPU cores (Intel Xeon E5620, 2.4Ghz), 30 GB SSD, 2 GB RAM.
Sites on VDS load several times slower. In ISP-Manager'e, under root, the peaks are not visible either by processor or by RAM. (The processor on the graph is 0-8% RAM is 25-29%.)
Why do sites on VDS, unlike Hosting, work so slowly? What would you recommend to add, RAM or Processors?

Answer 1

add brains
hire an administrator who would understand what the problem is
meaning to add percent if there are no peaks
meaning to add memory if it is missed

Answer 2

In descending order:
1. The hoster itself
2. Website
3. Server setup
In the case of Ihor, I think the hoster.

Answer 3

And of course, all VDS settings ended with the installation of the ISPmanager panel.
You think everything will be configured on the server by itself.
Hire a competent administrator or contact Ihor engineers , they have quite competent technical support specialists.