However, VPN connections incur additional overhead due to the encryption process; using higher levels of encryption would slow the connection even more. This can certainly be further reduced by connecting to gateways that have additional routing latency or have a lot of traffic on them at the time.
Slow VPN is basically a design flaw. Almost all VPNs work the same exact way. Your computer is connected to a remote server via a single secure socket. All of the data being sent to and from your computer or mobile device is first routed through the remote server. Or rather, I know how to make it faster, but do not know why it is slow. It seems that AES cipher interferes somehow with TCP on this particular server and results in the low performance. If I change the cipher to, say, 3des (which is slower as reported by "openssl speed"), I get 150mbps. After some trials, I now use this: Inside the (UDP) OpenVPN tunnel however, speeds would average at 21 Mbit/s - roughly 10x slower. (There is a significant latency between the servers: around 130 ms, and the transfers were measured using Iperf3 in TCP mode.) Tried all the suggestions on answers here as of this writing, and nothing helped. Jan 18, 2019 · lzo provides a slightly better compression ratio than the lz4 compression (available in OpenVPN v2.4 and above). It is however, considerably slower and uses more CPU. So you probably shouldn’t be using it unless for backward compatibility reasons. Worst-case scenario, using lzo might add an extra 1 byte of overhead for incompressible packets. Posted: Fri Dec 30, 2016 16:29 Post subject: Slow OpenVPN performance: I have a 15Mbps service and get 15Mbps with no VPN (don't laugh I'm on a Caribbean island). Using the Expressvpn app on my PC I get no noticeable drop in speed. However when I run openvpn on my Buffalo WHR-300HP2 (build 22750) it maxes out at 3Mbps. Oct 08, 2019 · To solve the problem of slow VPN speed, you might need to check the servers. The reason for the slow speed may be the wrong choice of server location. The farther the server is from your current
UDP is different from TCP. It doesn't have Window Scale but it doesn't need it OS-wide, but low buffer sizes may slow down it, too. If you think OpenVPN is still slow after changing buffer values to 0, you should either increase OS-wide buffer sizes (net.core.rmem_default and net.core.wmem_default) or increase buffer in server config:
Jan 18, 2019 · lzo provides a slightly better compression ratio than the lz4 compression (available in OpenVPN v2.4 and above). It is however, considerably slower and uses more CPU. So you probably shouldn’t be using it unless for backward compatibility reasons. Worst-case scenario, using lzo might add an extra 1 byte of overhead for incompressible packets.
May 03, 2020 · OpenVPN is typically the best protocol for both speed and security with your VPN, but if you’re encountering consistently slow speeds it may be worth trying L2TP/IPSec. It has less security, but may help you get past filters that are slowing down OpenVPN traffic. Apr 23, 2018 · Why Your VPN is so Slow Conventional VPNs are invariably slower than your regular internet connections because every data packet was encrypted and unencrypted through a remote server. These VPN connections also narrow the number of “channels” your data could go through. Apr 28, 2009 · OpenVPN and slow speeds I'm running an OpenVPN 2.4.x server on a Ubuntu 16.04 DigitalOcean droplet (their $5/mo one) and connecting to it with a Win10 client through a Comcast cable connection. The droplet is at DO's data center within 100 miles of where I normally connect to it. OpenVPN GUI bundled with the Windows installer has a large number of new features compared to the one bundled with OpenVPN 2.3. One of major features is the ability to run OpenVPN GUI without administrator privileges.