We have finally tracked down the outages and maybe also the sluggish performance on our mySQL server and we have found the RSS feed script for the forum to be the cause. I have disabled the feed for the moment and will add a new, proper solution as soon as possible.
I have just re-enabled RSS feeds using the new official feed introduced with the latest version of our forum software. Use the RSS button in your browser’s address bar (Safari and Firefox at least support this) to subscribe to the news boards, all boards, or the currently shown board.
All feeds always list the last 25 items. If you are logged into the user forum via Safari, your news reader should pick this up and also show you hidden boards (e.g. the beta tester boards) if available for your account.
As this should solve the problems with our mySQL server I have lowered the delays for searches to 10 secs per user (30 secs for guests).