To see your Mac’s current System Uptime (how long it’s been on, without a reboot), open your Terminal, and run this command:
The output will look similar to this:
David:david david$ uptime 8:54 up 19:51, 5 users, load averages: 2.18 2.44 2.67
As you can tell, you get a little more info than just uptime.
Let’s dissect each metric above:
8:54current time of the day
up 19:51how many hours & minutes my Mac has been on without a reboot
5 usersthe number of users (accounts on this Mac)
load averages: 2.18 2.44 2.67the average CPU load.
Mac computers are generally stable and don’t require rebooting that often. However, a good rule of thumb is that the older your Mac is, the more often you should reboot it. If you notice that your Mac starts to slow down, lag, or just behaving inconsistently, it’s often a sign that you should do a reboot.
As a reference, I reboot my MacBook Pro, mid-2014 once per day.
What is load averages about?
load averages values refer to how much of your total CPU has been used the last 1, 5, and 15 minutes (counting from left to right).
My Mac computer’s CPU has 4 cores, so a load average of around 2.0 means that I’ve only been using around 50% of my total CPU for the last 15 minutes.
Had my load average been 4.0, it would indicate that my CPUs are being utilized 100%. If your computer has 6 CPU cores, then a load average of 6.0 would mean your CPUs are being utilized 100% — you get the point.
Obviously, CPU load averages will go up and down when you jump from task to task, depending on how resource demanding it is. What you need to look for is if your load averages are constantly pushing 100%, because that suggests that you need a more powerful machine for the type of work you’re doing.