What is the speed of sending for your server

Question: I have a large list of subscribers that I want to send out very fast. What is the speed of your server? How fast can I send my messages?
Answer: To answer this question, it is necessary to understand how email works.
All the processing on the server is done extremely quickly. It is close to impossible to make it any faster. Moreover, since the CPU and memory of your PC work at the speeds vastly more supperior to the speed of your network, the speed of the software itself becomes almost negligible compared to the other factors. Now, the most determining factors of the speed of your connection become:

  1. Your outgoing bandwidth. This is the most important factor. Please do not confuse it with the incoming speed of your connection. Your ISP usually advertizes the incoming speed of connection, while the outgoing speed is not advertized. By no means outgoing speed equals to incoming speed. Most of the connections are asymmetric and the speed of sending is usually 10 times lower than the speed of receiving.
  2. Number of allowed simultaneous connections to the outside network. Some ISP's regulate that as well. They do not want to maintain huge number of connections and set a cap on how many a typical user can open. After that, each new connection will be refused or timed out. This affects how many outgoing connection threads you can set in your e-mail server
  3. Type of and number of messages and the destinations to which you are sending them. Each server to which you are sending your message to has its own speed at which it will accept your messages. Some target SMTP servers will accept your messages fast, some will be slower. Since each message is routed differently, speeds may vary greatly, so it is close to impossible to have a specific, concrete speed of delivery.
  4. Size of each message you are sending. Naturally, bigger messages will take much longer to deliver. Moreover, some servers may not accept larger messages at first try and you will have to redeliver.

All of the factors above make exact calculation of speed of delivery impossible. From our observations and the observations of our clients, you will need a dedicated 1 gigabit (1Gbps) Internet connection to your computer before speed of your software will start to have any affect on how fast you can send your messages.