The samsung EVO 840 (which is quite used around here from what I see) has been reported to have a bug with the firmware. http://www.anandtech.com/show/8570/...o-read-performance-bug-coming-on-october-15th Anyhows, Samsung has released a fix. The PC version was released a couple of weeks ago and the OS X fix just today. http://www.samsung.com/global/business/semiconductor/minisite/SSD/global/html/support/downloads.html Scroll down to "Samsung SSD 840 EVO Performance Restoration Software". Of course, to apply the fix, one has to do some sort of "DOS Bootup" sequence. A DOS bootup. I haven't applied the fix yet as quite honestly, I'm confused as to how to go about it. Anyone here have any ideas? Thank you!