High Performance Mode is slowest mode, compared to Power-Saver and Balanced Mode

Hello,

All of a sudden I've started to notice my computer has been running unusually slow. I searched for the problem and the solution, unfortunately I *think* I found the problem but I don't know what is causing it to do this.

What has been happening is that:

1. My CPU hasn't been fully utilized when it should be (ie: rendering)
2. My speed (Ghz) is severely lower than usual and seemed to be capped at 0.78 Ghz whereas my base speed is 2.21 Ghz and I know it usually overclocks to 4 Ghz easily - all according to the Task Manager

So, my original power plan was: High performance, with the default settings. I thought maybe the power-plan was glitched so I toggled it between Power Saver and High performance, and that's when I found this out:

When I switched to Power Saver mode, the speed immediately jumped up to the base speed and was unstable, which is fine. Switched back to High Performance, and we're back to 0.78 Ghz exactly. Currently, the Balanced mode is the fastest and goes over the base speed (which I expect High Performance to do).

Here are the things I tried to do:

• Windows Update - please do not ask me if I have the latest updates because you know I do.
• Intel driver update (none)
• Reset High Performance power plan to default settings*
• Changed the Processor "Start" registry from 3 to 1, 4. Now back at 3.
• Did SFC /scannow
• Did DISM checkhealth
• Did verifier - got BSOD error code: DRIVER_VERIFER_IOMANAGEMENT_VIOLATION - had to verifier /reset to get out of loop
• Stopped a few processes to see if any apps where controlling the processor - nahhhhhh
• Checked UEFI - doesn't have any relevant settings.

What I'm about to do is repair install Windows but I'm low on memory D: so this is going to be a pain. Is there anything else I can do other than re-install Windows?