EasyBitcoin-PHP very slow
This is likely implementation specific. Bitcoind is an intensive application to run on a basic server, especially if the webapp lives on the same machine. 

You should never directly connect a page's code with Bitcoin Core, for static information you should run a cronjob to update a cache every n seconds. If all you're showing is the last 10 blocks, maybe you shouldn't have every user at that moment triggering calls for the same data. 

Update: It's worth mentioning that RPC responses suffer a delay whenever Bitcoin Core is syncing, whether syncing for the first time, or being switched on after a day. This is because the block verification functions block for a while.