After switching to version 7.0.1 gtmetrix shows that Gravatar Cache is not working.
Despite the option activated in the settings of WpDiscuz.
In version 7.0.0 there was no such problem.
Please read the description of the option below:
There are two methods of Gravatar caching:
- Runtime – avatars are being cached on the first-page load, this method slows the first-page loading, but images are cached immediately.
- Cron job – images are being cached every 3 hours (default).
So in your case, you should use the Runtime method.