In my local host magento 2 running very fast but due to some reason i delete some files and module and then its speed becomes very poor and it takes approx 3 or 4 minutes loading its home page.
If you suddenly find that your Magento is massively slow after installing or updating a module, it might be this known bug where composer update turns off all your cache!
I know that this happens to me about once or twice a month. I now know to immediately go into command line and run
php bin/magento cache:status and I will see that all my cache is set to 0. Then I run
php bin/magento cache:enable and go on with my day.