when I be on the website (creating posts, browsing it...etc), the RAM usage goes up a lot! yesterday the RAM usage reached 5 GB!
the response time is unstable varying from 1500 ms. up to 5000 ms.
I don't think there's something wrong with the server because I'm hosting another website (that doesn't use WP) on the same server and it's response time is always 400-500 ms.
I tried deactivating all the plugins and changed permalinks to '/post id/post name' but it didn't change anything :(
any idea what's causing this problem and/or how to solve it?
additional info.
-the website is quite new (so there's almost no visitors at all except for me)
-there's only 12 posts on the website.
-all images are optimized in size & resolution.