If you checked Performance section in Site Audit report you might have noticed Time to First Byte (TTFB) chart:
If there are slow pages on your website, you may want to check on that more with a detailed report.
The report contains columns Time to First Byte and Loading Time.
In most cases Loading time is more than TTFB:
But it can also be very close or even identical:
It can be the case if there is little content to be loaded between, or if the bandwidth between the website and user is high. TTFB will mostly measure the latency between the website and the user. This will, for example, be network latency, or time that the website needs to compute the response.
Load time is the time needed to download the whole document, the difference between TTFB and Load time is the time the document is actually downloading. If the document is small, or the bandwidth between the user and the website is high, load time can be very close to TTFB.