bob16314
Make sure the BIOS is updated to Version 2804 which is the latest as of now.

Run a stress test like the Intel Processor Diagnostic Tool or Intel Burn Test that more evenly distributes load across all cores and see what you get..Be warned that those two tests will really get it cooking, so be sure to run the radiator fan at 100%, and watch the real-time core temps very closely.

Games/Apps will use/stress some cores more than others at times, so spiking sometimes will not be unusual..And your ambient temp is kinda high too.

Some BIOS settings that can help distribute CPU core load/voltage more evenly: Ai Tweaker -> SVID Behavior to Best Case Scenerio (to begin with)..Core Ratio to Sync All Cores at 46 (for a non-K CPU) or 47 (for a K CPU)..Internal CPU Power Management -> IA AC and DC Load Line to 0.01 mOhms..External Digi+ Power Control -> CPU Load Line Calibration should be fine on Auto at stock core ratio/Vcore.

What you really need to watch is the real-time Vcore under load..It may go way higher than needed with some BIOS settings on Auto.

Roll from there.

That cooler doesn't have the greatest reviews either, it seems kinda lame..It also may be failing like Sajin said.

jonkrmr
Looking at your last pic where you show voltages in HWInfo, I see your CPU VCCIO voltage is way too high.
Don't see CPU SA (system agent) voltage but suspect too high also.
Neither should exceed 1.25 volt (safe limit) and usually don't need to be set to that max safe voltage to get stability for CPU memory controller and memory for 3200MHz RAM.
Also, ASUS boards tend to kind of auto overclock the CPU by letting all cores boost to the CPU's max turbo over riding the stock CPU turbo multipliers by default.
Again, from your pics I can see your CPU running at 4300 MHz on all cores and assume they are boosting to 4600MHz on all cores, this would be ASUS BIOS setting doing that.
CPU is not overclocked so why are you using 1.27 volt for CPU?
Higher VCCIO, SA and CPU voltages = higher CPU temps.
The i7-8700 is a 6 core CPU and Intel used cruddy TIM between the die and heat spreader so they tended to run a little on the warm side especially when overclocked.
 

jonkrmr
The 1.25v max safe is for the CPU VCCIO and CPU SA voltages. VCCIO and SA feed the CPU memory controller. A lot of motherboards will run these a bit on the high side by default to ensure memory stability at the rated overclock memory speeds the motherboard will supposedly support.
voltage for these would be as low as you can go with maintaining memory\CPU stability. (I am running mine at 1.160v for both, but this will vary between motherboards and CPUs)
 
4600MHZ is the max turbo speed on a single core of the CPU. Yes, with MCE turned on the motherboard will clock all your cores to that max turbo of 4600MHZ on all cores when under a good load.
That is what MCE does, it over rides the default CPU core ratios and "overclocks" the CPU to the max single core turbo ratio on all cores.
Speed stepping is what is making the CPU clock to lower speeds when not under a load or light load. This is by design. But under enough load on the CPU, it will clock all cores up to the max single core turbo multiplier when MCE is enabled.
 
With MCE disabled, the CPU will follow its designed default core ratios and turbo ratios.
 
Your CPU will clock to any given speed from 3.2GHz to 4.6GHz depending on the load put on the CPU. CPU-Z stress test is not putting very much load on the CPU. Not a good stress test to use to check for stability. Your games are going to push your CPU a lot harder. Especially games that are CPU heavy.
 
AIOs are fine but really do not perform much better if at all that a good air cooler.
 
I am able to run my 8700k at 4900MHz on all cores all the time and 3200MHz RAM with 1.25v for the CPU and 1.160v for VCCIO\SA. Can go higher but voltage required starts to jump up a lot and then heat starts to become an issue.
 
I am not spiking over the mid-high 60s on my CPU but I am using a custom water cooling loop with a high flow pump and a 240 and 360 radiator. Am also water cooling my GPU. CPU idel temps are around 28-30 degrees depending on room temp.