Sometimes update_help() execute ages, Drupal freezing

I've spend couple of days to figure out that update_help() spend around 120-200 seconds on hook_help() each time, when website is loaded. My Drupal website is not usable with this module. I'd to disable update module.
Any known bugs or ideas?
It's possible to optimise it somehow?
Updates shouldn't be not done by hook_cron?

Tested on heartinternet server.