Does installing an SSL certificate (HTTPS) slow down the site?

Using HTTPS does not make your site faster (it is actually possible, see below), but there are some tricks that can greatly reduce the extra overhead. First, as long as the text content is compressed, it reduces the CPU resources that are consumed by decoding. However, this overhead is trivial for modern CPUs. Second, an HTTPS connection is required, requiring additional TCP round trips, so that some bytes are sent and received.                                 However, as you can see from the image below, the number of new bytes is very small. The first time you open a webpage, the HTTPS protocol is a bit slower than the HTTP protocol because of the time it takes to read and verify the SSL certificate. Below is a waterfall diagram of the time the HTTP Web page was opened.

After the same Web page uses the HTTPS protocol, the opening time becomes longer.

The part that establishes the connection is about 10% slower. However, once a valid HTTPS connection is established and the Web page is refreshed, there is little difference between the two protocols. First the HTTP protocol refresh performance:

Then the HTTPS protocol:

Some users may find that HTTPS is a bit faster than HTTP. This can happen in the internal LANs of some large companies, as the company's gateways typically intercept and analyze all network traffic. However, when it encounters an HTTPS connection, it can only be released directly, because HTTPS cannot be interpreted. It is because of the lack of this interpretation process, so HTTPS becomes relatively fast.
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