You mentioned that you are using XAMPP. I too lived with severe XAMPP performance issue in my local development environment for a months, believing that the extreme poor performance was due to my ageing computer. I avoided using it whenever possible because it was so slow.
One day I tried out an alternative to XAMPP and could not believe how much faster it was. It was literally 10 times the speed! Pages that loaded in 30 to 60 seconds now appeared in just 3-6 seconds. That's a 1000% improvement. I was just about to dump XAMPP completely when I decided to see if I could figure out which configuration setting that was causing this, after all, they were both running the same version of Apache, PHP and MySQL. Slowly I migrated settings from one the fast instance to XAMPP and kept re-testing performance. Most settings had negligible effects and some even made things worse. I was running out of settings to migrate when it finally happened - XAMPP became just as fast! You would not believe how happy I was.
If you have XAMPP configured with XDEBUG, that may be the source of your troubles too.
So which setting was it that caused the problem? One of XDEBUG's options will literally kill the speed of your Moodle installation: Profiling.
xdebug.profiler_enable = 0
If this setting is set to anything other than "0", Moodle will slow down to a crawl.
I wrote an article on configuring XAMPP to work with NetBeans on Windows. Although it doesn't mention Moodle in particular, that is exactly what I was doing when I wrote the information.
Hope this helps.