The answer is "yes." In my experience, VPNs are generally slow. Using a VPN is always going to be slower than not using a VPN because of several factors:
- You're forcing traffic to go through the VPN, which may not be the optimal path (especially if traffic is then going back out to the Internet).
- You're adding a couple of extra devices in the path of the traffic, and every device adds some latency.
- Some encryption and decryption needs to occur, which requires math, which is processor intensive.
With that said, items No. 2 and No. 3 don't need to cause a noticeable performance decrease as long as your VPN device is fast enough to handle the traffic you're throwing at it.
This was first published in August 2003