Could anybody list possible reasons why QMC can be very slow. It all works, but it can take between 5-10 minutes to respond to any of the clicks that I make (e.g. like switching between tabs, expanding folders etc). It's becoming quite frustrating!
If you have checked that your system isn't on his limits (CPU + RAM via taskmanager) I would clear the browser-cache and restart the qmc-services. Are there then further significant delays then is something between the communication from the services wrong. You should also check if the browser-communication runs over any proxy-services which could also delay the response-times.