VPN with Encryption gives twice the download speed?

Question

I am currently paying for internet through SuddenLink which has offered me 50Mb download and 3MB upload. I have also bought a VPN through PrivateInternetAccess, which has pretty much doubled my download speed while downloading files encrpyted from my ISP.

The speedtest.net has shown with the VPN running with 128Mb down and 10Mb up.

Please Note The Data Encryption is BlowFish, Data Authentication is SHA256, and the Handshake is RSA-4096.

I have been told that this is not possible at all by several people, but when I go to show them the results from actually downloading a file and the speedtests, we are all confused.

Is this actually happening? As they are asking and were saying, is it the speeds which we see from the end-point of the VPN to the server which we are preforming the speed test to?

Also, I will provide screenshots of the speed test with and without the VPN also.

Update 1

I am not sure if this matters or not, but it may in the end. I live in a very, very rural location in West Virginia. I am lucky to not have 256K Dail-up internet thanks to my ISP, SuddenLink. I am starting to think it could be a congestion issue with my region?

Answer 1

In the past I have had the same effect with my ISP (in a rural area too, though this is but a coincidence).

The root of the matter was that he implemented a bandwidth limitation on port 80 only. This was especially obvious with speedtest.net, where the initial speed would peak, then decrease to less than half of its peak value.

I discovered by pure chance that this did not occur on OpenVPN, where I managed to obtain the peak speed value during the whole speedtest.net test. This was made possible by the fact that the site I connected to (my work site) has a very nice, very fast, large-bandwidth connection.

Alerted by this, I tried a large file transfer via scp, and, lo and behold, I achieved the same large speeds as with the OpenVPN, rather than the lower http speeds.

You may try the same, and see whether a bandwidth limit is applied on ports 22 (scp) and 21 (ftp). It is most illuminating to use files already significantly compressed like pdfs, since this will rule out the incidence of compression per se.

Though admittedly sloppy, these bandwidth limitations are still effective, since most people use the Internet only for downloading Web pages.

EDIT:

Strictly speaking, there is a way to test this: if you control the VPN server, you may stop any other activity on the server on port 80, and start listening for VPN connections on port 80; you will also have to modify the port you connect to on the client's program. Now, if your ISP is limiting bandwidth use on port 80, the VPN should clock at exactly the same speed as the non-VPN connection.