At the highest level, Speedify does two big things to help speed up your Internet:

1. It lets you combine the bandwidth of multiple Internet connections
2. It detects and re-sends lost packets
3. It does all this with a VPN twist, encrypting your online traffic to protect your privacy and sensitive data

So, I set up two identical 3 Mbps Internet links, with 50 ms round trip time as latency, and then slowly dialed up the loss.

I tested with 3 software setups:

• 1 Connection, No Speedify – Just TCP on the Internet.
• 1 Connection with Speedify – Speedify running on a single Internet link
• 2 Connections with Speedify – Speedify running, allowed to use both Internet links.

The results were as follows:

A couple observations:

1. Speedify added about 3% overhead to the single link, making it .1Mbps slower when there was no loss.
2. But as the loss increases, the “No Speedify” throughput collapses. At 5% loss the throughput is down to about 25% of full speed. (And this can be a real scenario with WiFi, by the way)
3. Speedify offers great protection from this loss. At 5% loss, it’s 234% the speed of TCP without Speedify
4. Bonding Works! Even with no loss, the Speedify 2 Connection speed is 193% the speed of just TCP on one link (96%) bonding efficiency. This is especially critical in bandwidth intensive applications like Twitch gaming, video streaming, etc.

Your mileage may vary, in particular:

1. Speedify does adjust to non-identical Internet links to allow them to be bonded. But as the latencies and speeds get further apart, the bonding efficiency does come down.
2. How badly TCP is affected by loss is affected by latency. At higher latencies, Speedify can end out doubling your performance at just 1% loss.
3. We were then focused on combined speeds of up to 50 Mbps, this was not (yet) a service for Google Fiber users.
4. I didn’t talk about Redundant Mode at all… usually lower throughput but delivers very consistent, non-jittery performance (lower average ping times).