Yosemite has brought Safari to its knees

During a day of using Yosemite, the spinning wheel of sleep has appeared more frequently than in 10 months of Mavericks. I’ve cleared the cache. I’ve deleted the Cache.db file (~/Library/ Caches/com.apple.Safari/Cache.db). I’ve quit and relaunched Safari. I’ve added no extensions. My download speed is always greater than 50Mbps. Ron Hughes Deleting the cache files is a good first step, although you also need to reboot afterwards and empty the Trash for it to take full effect. I haven’t experienced this Safari slowdown on any my Yosemite Macs, but I’ve seen a lot of reports that implicate connected cloud services like DropBox and iDrive. Disconnecting and then reconnecting them has fixed the issue for some people.

Other suggestions – including resetting the System Management Controller and the non-volatile RAM – seem suspect. The NVRAM stores display resolution, speaker volume and other settings for directly attached hardware, not devices accessed over the internet. Likewise, I’m sceptical that significant memory leaks or other bugs have made it past Apple’s QA process. So my money is on connected cloud drives.