Since speed is a hot topic for our users, we decided to write a post about this and explain how speed levels differ when using a VPN connection and when you are connected to a normal Internet connection.
When using a VPN connection, all data is divided into packets before being sent. These data packets are then encrypted with AES-256 bit. This is a complex and computationally intensive step. After the encryption, more control information is set before the data (Header), so due to additional information every packet is bigger as it originally was. This so-called “Overhead” is proportionally bigger, the more small packages are sent, since the control information have a fixed size regardless of the size of the original packets. For example, at CyberGhost (via OpenVPN) this takes approximately 50 bytes per packet (it varies depending on the setting for encryption, authentication etc.).
The size of the data packets depends, among other things, on the following: over which servers are these sent and which packets size does the remote station accepts (MTU).
At the measurement of speed tests with active VPN connection is measured only how many user data can be transmitted over a period of time, therefore the above-mentioned Overhead is not measured.
So before you ask us why do you have small speed on your servers, it’s important to define „small“. Should you reach on all servers speeds less than 4 Mbit, although your internet connection can do far more (you can test this on speedtest.net), you may assume then there is a problem on your PC. To check this, please test the VPN connection with sufficiently different servers at different locations (at least 3). If the results are all over bad, it means there is a problem on your PC.
You can read all the explanation of the speed problems here, on our forum:
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