If you have a laptop that is running dramatically slow sometimes, and everything in the machine and operating system has been checked out ok, it may be down to your power adapter.
I know it may seem odd that a power adapter could cause this issue, but if it is not providing the exact voltage some machines need, the machines CPU will drop down to 10% of its potential speed.
You can test if this is the case, by unplugging your power adapter from the laptop, setting the power settings to maximum performance (no power savings) and checking if the slowness still exists.
