Make sure you are running the latest Intel XTU
if possible access the bios and reset the settings to default. Besides this, make sure the power options are configured to balanced or maximized.
Dude I was having the exact same problem since I upgraded my laptop to Windows 10.
And just now, I found a solution. It is to download a software called ThrottleStop or you can just click Download ThrottleStop 6.00 | techPowerUp
Don't worry, this software is completely virus free.
1. Download it.
2. Extract the .zip file to a folder.
3. Open the extracted folder and double click on the .exe file.
4. Set it exactly like this...
5. Click "Turn On".
6. Click "Save".
7. You can close the program now.
Whenever you get the 0.98 GHz problem, you can always repeat from step 3 or you can make a shortcut to your desktop to make it faster to reach.
I'm hoping this method will work for you as it works for me. Let me know if it does