Was proof provided that performance would be affected? The only time I have ever seen anyone say this is when JJ at ASUS said it in this guide:
There's no formatting so it's hard to read, but here's an excerpt (edited slightly):
K series overclocking and its affect on subsystem performance (especially hard drive performance)
Quick note regarding options that can affect subsystem performance:
It is NOT advised to make adjustments to C-States because this can considerably affect hard drive throughput performance (especially SATA6G SSD or Sandforce 2-based SSDs). It is recommended that all CPU power configuration states be left on their default parameters. Overclocking tests have shown internally no increase in multiplier scaling when adjusting these values. Under special cases with high multi capable CPUs and synthetic high load applications (LinX, Prime, Occt), C-States may need to be disabled. This has generally only been confirmed for some 51-54 multi capable CPUs.
As you can see, it's really only an issue when overclocking, especially to extremes (like taking Sandy Bridge to multipliers of 51-54 as he said here). I'm not saying I think your laptop is a Sandy Bridge system, I'm just saying I think that this is where the belief came from that you have to disable C-States no matter what if you have a solid state drive.
Edited by TwoCables - 12/20/16 at 11:22pm