I think it's quite good, but @done12many2 is the X99 expert

@JurunceNK  You might want to share your VCore if you are looking for feedback on how decent the chip is.  While VCCIN matters, it's not nearly as much as VCore, VCache, IMC voltages and the like.

I suspect that you might be sharing VCore labeled as VCCIN buy your motherboard or yourself and in that case, I'd say it's decent depending on how you tested it?

Congrats on the overclock bud.

CPU Core Voltage settings are Adaptive Voltage, with the Additional Turbo Voltage set to 1.205V, which results in HWiNFO64 reading it as 1.214V. Using a DDM on the back of the socket reads higher, and I don't know what that voltage will read with 1.205V typed in.

CPU Cache, System Agent, and CPU Input are all left at stock voltage. Increasing these results in higher power draw at idle, which is something I try to attain so when I'm doing light tasks, it doesn't burn power for nothing. RAM is manually set to 2666 MHz 14-16-16-36 1.2V

I tried to also increase the CPU cache while maintaining the adaptive nature, but this resulted in the system not booting due to insufficient cache voltage during initialization. I get stuck at code 95 (pci bus request resources). Plus for what I do, I found that increasing the cache frequency does almost nothing unless I do 4K video editing, which is something I don't do.

I used AIDA64 and playing some Final Fantasy XV Windows Edition to test the overclocks, since I do use this system for content creation where I render on the CPU, and gaming on it. The game in question I found can leverage the 12 threads rather well. 

CPU cache overclcocks and memory overclocks will directly impact your results for CPU overclocks.  This is to say that the lower you go on cache and memory OCs, the more you're likely to get away with on the CPU clocks themselves at any given voltage.   Really simple if you think about it.   More cache speed combined with faster memory puts more data across the CPU package, therefore increasing load on the CPU itself.  More load at the same voltage results in less stability.

CPU Cache adaptive voltage on Asus x99 motherboards is broken.  It doesn't work on x99 or x299.   Offset is what I recommend over manual voltage in this case.  If you try to OC the cache with voltage set to adaptive it just won't work, which is what I believe you are experiencing.  I ran 4.4 cache on my 5960x with a very small increase in voltage over stock (~1.2v).  I don't recommend exceeding 1.3v on the cache and you're probably better off staying below 1.25v for extended load situations.  

If your goal is to maintain good power draw at idle, than you may want to stick with what you have now.   If you want to get the most out of your CPU, definitely increase CPU cache as this directly impacts memory performance (both latency and bandwidth) on x99. 

As far as testing, AIDA64 or anything for that matter is great as long as it is more stringent than the actual loads you will observed during daily use.   No sense in setting your voltage up for a Linpack or Prime95 load if you never plan to subject your CPU to those levels of load.  With that said, it's really hard to tell people whether or not they have a great CPU.   Everyone's version of stability is different.  I can tell you that your chip definitely doesn't suck.  

Have fun with it!