Fix random lengthy pauses in OS X by correcting bad blocks
If you find your Mac is running slowly, generally there are a few things you can do, including running a general maintenance routine, deleting unneeded files to keep at least 10 percent of your boot drive free, increasing the installed RAM, and quitting unused applications (both foreground and background) that you may have installed. In addition to this, one possible cause of slowdowns is if your hard drive contains undetected bad blocks, and forcing the system to remap them can result in things running smoothly again.
Hard disks are "block-based" storage systems, meaning that their writing surfaces are … Read more