Maintenance :: CPU Throttle On Windows 8 During GPU Intensive Applications

I have recently upgraded to Windows 8 from Windows 7. I experience CPU throttling whenever I run GPU intensive activities. For instance when running Crysis 3, I have a constant fps of around 40 and then after a few minutes there is a barely noticeable black screen flash after which my fps drops to around 4fps. On MSI afterburner my GPU usage stays constant at 99%, but my core clock, shader clock and memory clock drops significantly:

This is not due to temp. It stays constant at around 70. I have also tried changing the power options for the processor (Min Processor states). No change. I have also used throttlestop to disable the BD PROCHOT, EIST, C1E. Still no change.

Everything was fine on Wind 7. System specs:

I also have a Toshiba Dynadock usb 3.0 which underperforms w.r.t responsiveness. It uses Displaylink drivers. I have removed all the Dynadock's drivers and unplugged it. No change. I have also updated my Nvidia drivers. No change.