56K, ISDN 64/128kbps, DSL 256/512Kbps, ADSL
12/480Mbps, Network T1 (1.544Mbps) Cable, does
not mean that you can have the same up-load speed.

Why is the speed of broadcasting
my emails not consistent?

Inconsistent mailing speed are due to various factors from line (static's), Internet peak-hour congestion, throughput, sender or ISP mail server busy, using of non dedicated mail server, sharing of mail server with other functions/users, poor maintenance, etc.

Sender mail server program used (single thread) server microprocessor capability/capacity and how many companies or users sharing the same network/cable Internet connection, etc. are just some of the contributing factors to inconsistent emailing speed.

You can PING the mail servers or if you are using your own mail server PING the Internet to determine connection throughput.

Throughput, bandwidth? Are the outgoing and incoming datagram Bits-Bytes between your computer, ISP connection and the Internet network.

What is the speed or how many emails
can be broadcasted per hour?

MailsBroadcast send emails continuously in groups of 10 (default setting) or up to 250 emails per group to your ISP mail server or to your mail server program for delivery--as fast as they can cache them for distribution. Therefore, the speed of sending emails is not due to "MailsBroadcast".

Broadcasting speed are usually between 500 to 5,000 text emails per hour using 56K or ISDN 64/128Kbps, your mail server program, ISP or Internet connection bandwidth or throughput which are affected by various factors from line connection (static's), Internet peak-hour congestion.

DSL, ADSL, Network or Cable connections are also subject to the same throughput, up-load speed, congestion problem or number of users/companies connected at the same time during peak hours and sharing the same cable Network.

Different ISP provide different up-load and download speed--meaning that having a 56K V90/V92, ISDN 64/128kbps, DSL 256/512Kbps, ADSL 12/480Mbps, Network T1 (1.544Mbps) Cable etc., could represent download speed and up-load speed could be 20-40% lower, check it out with your ISPs.