TTFB在一台计算机上太高，而在另一台计算机上没有

I have a web app for hotel that monitors guest checkin running in PHP/MySQL.

The checkin interface is composed of ajax calls that return data for a checkin to complete. The server where the web app is installed has a TTFB of 3.58 seconds.

What I did is I copied the web files and the whole database for comparison. I installed xampp on my computer. Tried to run the same process, I got 100ms.

There are not much differences except that their server is faster than my home computer. All files and database is the same. What could be the culprit?

Here's my screenshot of Chrome's debugger tools (Home computer)

And here's their server

I hope I provided all the information you guys need to troubleshoot the issue. I appreciate all the help I can get. Thank you.