I have 2 woocommerce site in management.
Together is 10gb of files and 200mb of database
Both are on a dedicated server managed with 32gb of ram, 2x500gb ssd, intel i7-6700
Cache it's installed, theme is optimized, but some time it's slow.
How can i do to improve fast?
There are a lot of things involved. I manage servers and even websites or applications hosted on those servers and its just not the server configuration or website cache enabling. There is so much more to it. Sometimes, there is just an error_log file that is too big and making your website slow. Sometimes some imature plugin is filling up your database with unecessary information which they normaly remove by cron but sometimes that cron is not working or timing out because the database is already too huge and your my.cnf file doesn't allow enough time to a query to clean up the table. Sometimes there are too many transients in the Wordpress that are making wp_options table too big. I am not saying that server optimization and Cache doesn't matter. It does obviously but there are a lot of other things that can cause the website to be slow. I manage websites that rank in the top 100K in alexa and faced such issues few times. You have to monitor server load, check MySQL and Apache processes. Use Query Monitor WordPress plugin for a start to see whats taking too long. In the case of WordPress with many plugins, there is so much to look at when you face a problem.
If you already signed up for managed services, then may its just for the server and not for the website. I provide manage servers that cover website maintenance as well which comes with security, optimization, and backups of servers + remote backups (on separate server) as well as websites'.
If you need any professional help, let me know.