I don’t really know how to explain what’s going on with my Mac, so bear with me. Since a few months ago my Mac started to lag. It freezes for a seconds or so then comes back. And it happens almost every minute. At first I thought it was caused by some open app, so I restarted the Mac and it kept happening – even though I was only using Finder since I restarted. Then I tried repairing disk permissions and nothing changed. I tried I clean install of OS X and it’s still the same. Tried to reset SMC and NVRAM, still no change. I tried keeping track of Activity Monitor and logs but nothing unusual seems to show up. On Activity Monitor, under Disk tab, the freezes sometimes are in sync with data written/sec peaks. Any ideas what could it be? Here are my specs: MacBook Pro (13-inch, Mid 2012) 2.9 GHz Intel Core i7 8 GB 1600 MHz DDR3 Intel HD Graphics 4000 1024 MB 750 GB SATA HD OS X Yosemite 10.10.4 Please help! It’s almost unbearable to use my Mac right now. I can’t listen to music or write anything without if freezing every ten words. EDIT: Solved. It was being caused by a dying HDD. I switched to SSD and now my MacBook is even faster then when I first bought it!