Significant lag on Mac OS X 10.7.5

Question

For the past 2-3 days, my computer has been lagging enormously. I cannot explain why this is the case - usually I have 50+ tabs open in Chrome, Colloquy, iTunes and a handful of other apps running at the same time, with little trouble (on a 1.7ghz 4gb 256gb 13" 2011 MBA). I have checked my memory and disk usage - I have over 700mb ram left, and almost 30gb of disk space. CPU usage is absolutely minimal, and there aren't any external displays connected.

What I've noticed is that many apps are performing with a significant lag when typing and scrolling - it sometimes gets to the point where I cannot type a sentence without the 'other letters' menu popping up (accents and symbols menu). Scrolling is also usually quite smooth, but now it's really botchy. I also tried playing a 1080p movie in VLC (which usually plays flawlessly), and it just kept dropping frames like it's 2006.

What have I done to remedy this? I have restarted the computer, I have closed all chrome tabs that I do not absolutely need, and ended the process of all tabs I currently wasn't using. I do not recall changing any critical aspects of the OS since the start of this nonsense.

Answer 1

It sounds like you have done a lot of through investigation. Your next step is to identify if this is a hardware or a software issue.

First try and rule out hardware

Hardware

• Hold the shift key while your mac boots up, this will put it into safe mode. If the problem goes away, then this is a software issue.

• Find an apple store who will run a quick netboot. This will generate a report of any hardware failures.

• Boot from a separate install of OsX. If you have a spare usb hard drive laying around, install Mac to it, and boot of the external drive. If the problem goes away, then this is a software issue.

Software

• Verify your primary hard disk in disk utility, I've seen similar issues when my Catalog file became corrupt.

• Create a new user account, and see if the problem goes away. I find creating a new account often can fix some of the minor issues that would otherwise require a format.

• Open the 'console' app inside the utilities directory. It will show real time logging of all the apps on your machine. Google any errors or warnings that pop up.

If you have ruled out hardware as the culprit, and you have further investigated the software steps outlined, then it is usually easier to backup using carbon copy cloner, or time machine, and install OsX fresh.

You could alternatively take it to a repair shop, and they will do all these same steps for you.