Kerry Wan/ZDNET Follow ZDNET: Add us as a preferred source on Google. ZDNET’s key takeaways Clearing cache speeds up a slow Galaxy Watch. Cache buildup can cause lag and drain the battery. Restarting isn’t enough, so you’ll want to manually clear the cache. Your Galaxy Watch is not so different from your phone or even a messy room. When put to great use, it, too, gets cluttered. By continually using your Galaxy Watch, regularly switching between apps and functionalities, or run...