Check Your Task Manager
First of all, check your Task Manager. There are many ways to access it, here are a few ways to do it:
Type in taskmgr in the Start search box, or
Hold down the Windows key and then press X, or
- Right-click on the taskbar at the bottom of your screen and select Task Manager
Click on the Performance tab and check on the Speed of your CPU. A normal, idle CPU when you aren't actively running any programs should hover around 1.0 to 2.0 GHz like what's shown above. Its value should also fluctuate constantly, i.e. it should be jumping around from 1.05 GHz to 1.34 GHz, then back to 1.10 GHz, up to 2.15 GHz, and so on.
When the lag happened, my CPU speed was stuck at 0.19 GHz and there was no fluctuation. So what did I do next?
Force a Shutdown and Restart the Device
Admittedly, I ended up resetting my whole device, effectively removing all my data. It was not that big of a deal because most of my personal files on my Surface Pro were already backed up in the cloud. But don't do this, because it did not fix the problem!
When I reinstalled Windows after the reset, it took hours, supposedly because it was still running on a CPU that was somehow stuck at a low speed.
Suddenly I realized that I've been leaving the device on top of my thick bed duvet, which trapped heat. So I sat the device on the cold hard floor in my apartment and the reinstallation went whoosh—it was completed not long after.
But even after that, I had the same problem. It was still laggy.
After fumbling around with the device, it turns out the fix was simple:
While the device was on, I simply pressed and held down the power button for about 20 seconds, which forced it to shut down and restart.
Voilà. Problem solved.
My Surface Pro was back up and running at its usual speed, the CPU speed in Task Manager was shown to be fluctuating and I can't believe how simple the solution actually was.
I hope this helps!
Got another tip? Leave it in the comment section below.