Since the Core i was introduced in 2008, the C states have been getting blamed for stability problems. The real problem is when you enable the C states, the CPU runs faster when lightly loaded.
What sort of stability testing have you done? Are you using the default BIOS settings for voltages? Are you full load stable? Do these issues only happen when lightly loaded? Can you run Cinebench R23 for 10 minutes without crashing?
A lot of people buy a collection of random parts, set the BIOS to default settings and expect that their new computer will run trouble free. That rarely happens. It can take a lot of testing and a lot of adjustments before a new computer will run like it should be able to run.
What motherboard are you using? For future reference, it is usually easier to get 2 x 16 GB memory modules to run stable compared to 4 x 8 GB memory modules.
For desktop computers, I prefer to lock the CPU to a single speed. I find it is a lot easier to come up with a stable system by doing this. You can set all of the turbo ratios in the BIOS to the same value and then in Windows you can use the High Performance power plan.
Some people think that having a computer run at full speed when it is idle or lightly loaded is a terrible thing to do. It is OK to do this if the core C states are enabled. You can have a fast computer, excellent stability and low idle power consumption, all at the same time.
For my 10850K, I decided to run it at a steady 5000 MHz. At default settings the 10850K can run at up to 5.20 GHz when lightly loaded. I decided to decrease the maximum CPU speed so I could reduce the peak voltage. The default full load speed is 4.80 GHz so I bumped that up to 5.00 GHz. Some users are shocked to see that power consumption and the CPU idle temperature is excellent when running at full speed. It sips power like a notebook.
The individual cores are averaging over 99% of the time in the low power C7 state. In this state the cores are sitting dormant at 0 volts and they are disconnected from the internal clock so they are sitting at 0 MHz. That is why idle power consumption is excellent.
I would start by thoroughly testing your computer with the C states disabled. You want to be 100% stable when fully loaded or lightly loaded. Then you can enable the core C3 state in the BIOS and see how that goes and then enable the core C7 state.
You can leave the package C states disabled. I have package C2 and package C3 enabled. The core C states are the important ones. A stable computer should still be stable when the core C states are enabled.
If you are still having issues, run HWiNFO and post some screenshots of your voltages. It can take some voltage tweaks to the SA and IO voltages to try and get stable. You might also have to pull two memory sticks to see if maybe your memory is causing your stability issue.