Can I change the amount of memory used for caching?

I have configure APCu to be used for caching. I have enough ram in the system to have more files in cache if needed. Is there a way to configure this?

Also, I have configured a cached directory to use in my config/config.php
’cache_path’ => ‘’,
I do not see any files being added there, should I see them?

Thanks

Not sure if you have options in the apcu config. If you have enough RAM check you database caches (mysqltuner, priming-tuner script help)

I am not too familiar with SQL. Is there perhaps a guide to follow that explains your answer?
Thank!