Update:
I got a hunch again on all this and went into my box's UEFI to look more closely into my CPU's advanced core settings and found the CPU EIST Function setting (this setting is what controls Intel Enhanced Speed Stepping at the CPU level from the UEFI) so I set the UEFI to disable this function in my I7 5820K CPU, saved it, rebooted then checked this thru Gigabyte's SIV......my CPU is showing now to be locked solely into Intel's TurboBoost function w\ CPU consistently clocking between 3900-4003 MHz (this is set in my UEFI's CPU Upgrade setting). So this will not be fully disabled thru the Windows Power Management scheme of High Performance....only at the UEFI\BIOS level.
Went up using AHIII Dx11 using all 6 CPU cores to test..............testing has now confirmed that it was Intel's EIST that was causing the petite freezes while running under Dx11 due to the low CPU core loading. Here is a snippet of MSI AB graph showing a pretty clean GPU frametime graph line now w\ all 6 CPU cores being used and Intel EIST disabled in the UEFI......
However, you will also note that a screen pause was also recorded and when I moved the white synch line over the large GPU frametime spike then traced down to the CPU core usage this showed once again to coincide w\ CPU core usage % to be less than 35% on any active CPU core which is following the same pattern of all other screen pauses that I've captured since I set up the individual CPU cores to be graphed.
I'm gonna run some more tests w\ CPU affinity cut to the optimum CPU core numbers that have shown the AHIII game client to run the best under w\ EIST disabled to see if the screen pausing ceases..........but I don't see this happening unless the CPU core loading goes up enough to keep up w\ a fully optimized GPU at full GPU clock speeds.....and this IMHO can only be achieved thru the game client software OR me making setting changes to try to slow down the GPU to better "synch" w\ the current CPU game loading w\ AHIII Dx11.
IOW's I believe these screen pauses are due to a timing issue created between the CPU\GPU being influenced by the AHIII Dx11 game client and\or other external factors that shows up once the CPU core usage % drops below 35% on all active CPU cores. Again I'm NOT making any claims that the AHIII game client is BROKEN under Dx11 so don't take this there.
What I will suggest is that maybe the AHIII game client could use a little more tweaking to make more use of the CPU cores relative to the current usage model to raise the CPU core usage or loading up some more OR raise the post-processing rendering levels\GPU work load levels as hard coded in the AHIII game client to work the GPU some more to effectively slow it down just enough to "synch" better w\ the current CPU loading when running under Dx11.....but this may not be feasible IF doing this breaks the game client from being able to qualify for VR certification.....which is what I'm kinda suspecting would be the quandry at hand at this time. As for running under Dx9 the game client needs no further enhancing work done to it that I can detect.
Just a hunch....................
If I may ask, is there any way that I could talk the nice folks at HTC to consider to write into the game client coding the instructions to instruct the OS to assign CPU core affinity so when the game is started up the optimum number of CPU cores to be used will be automatically set up? I know I'm asking for a lot here but I REALLY like how the client performs when the CPU cores being used are limited to 2 total CPU cores and I KNOW that MS ain't gonna go there............
You do realize that Christmas IS just around the corner and Santa would love it as well while he's flying his sled in the game that he has put the insignia of Johnnie Johnson's Spitfire Mk IXe on the sides of it.......maybe w\ a case of a little something, something wet and over 81 proof thrown in to boot.................
Yeah I know this was bad but I just HAD to try................