You should also be careful with the implementation of the VPS and the central software behind it, within the Linux VPS that has
OpenVZ (or Virtuozzo): this is a very shared option of system resources and, although not always, it is sold in excess, which means that the performance varies greatly from one day to the next, from one hour to another, from one minute to another. The advantage is that it is often the cheapest of types.
KVM: this is the most common since the use of predetermined configurations from a server level provides the best performance. RAM and CPU can still be easily oversold, but not as common as with OpenVZ.
Xen: can have a better performance if the hosting company takes the time to customize its configuration files, the CPU can be oversold, much more difficult to sell.
VMWare: Few hosting companies use this, but they offer a good performance balance compared to KVM and Xen. Since it is a commercial product, often these solutions will be a little more.
HyperV: often used in Windows VPS, because it provides true virtualization for Windows.
There are some others that are less common in the industry.
The other thing that you should keep in mind is a VDS (Semi-Authorized Server). This option does not allow the excessive sale of CPU or RAM, since the resources are dedicated 100% to your account. Often you also get dedicated hard drives. This option may not give you the performance faster than other solutions at the moment, but it will always give you the same results. However, you will often pay a little more for this option, and the hosting company can not share any of the server resources between the clients.