openHAB performance issues / lag

I’ve recently added some additional items to my home.items and added authentication for remote connections.

Since doing so I’ve noticed that the openHAB UI through a web browser and the iOS have becoming quite slow and laggy. It takes about 10-20 to load each screen and navigate from menu groups to items.

Checking ‘htop’ the openHAB process never seems to be above 7% CPU usage. So it seems to be in range.

The home.items file has approx 4 lights in it, 4 groups, 2 switches and a couple of date time variable labels. So nothing complex.

Are there any performance tweaks I can do to speed up the UI?