You coming from other Webhosting? Some webhosts have own integrated cache system.
Have you wordpress site? Install plugins like WP rocket, Fastest cache...etc
Activate in PHP the OPcache and Memcached.
Have you OLS, Nginx or Apache? All have settings, OLS have LScache, Nginx.... etc.
Settings anywhere set, what you have, how many Ram, etc...
And when all have, try again test.