Ok, I think I solved massive stuttering with the NGXu and other most likely other CPU intensive addon aircrafts. I was also hearing annoying audio popping and crackling lately, and today I did some googling and found the post where one guy was listing the processes and stuff that can cause it.
One item was intriguing - Intel Rapid Storage Technology. I know that I have it installed, so I rushed to Add or remove programs, uninstalled it along with EVGA Precision XOC (didn't used it), restarted the PC.

Fired up P3D, loaded NGXu, and voila, pretty much smooth performance with unlimited frames! I literally forgot what it looks like, I'm used to locking down the frames to 1/2 of refresh rate.

I will still use locking the frames though with RivaTuner, as it's the smoothest performance you can get (completely stutter free buttery smooth).
I was also testing performance settings in the NGXu FMC, and found that PFD and ND set to -- (00) it's far the smoothest (check the pic below).

If you have Intel Rapid Storage Technology installed, and experience stuttering, try uninstalling it and test. 

Here I also have IRST installed but no stutters or whatsoever. As I do not use the PMDG perhaps that is the cause...

I am glad that you have solved your issue 👍

Same here, IRST installed and no stutters, not in the NGXu or elsewhere. I bet it was the other software then 🙂

19 minutes ago, AnkH said:

Same here, IRST installed and no stutters, not in the NGXu or elsewhere. I bet it was the other software then 🙂

Strange then. I really can't pinpoint to EVGA Precision XOC since it was on default values (no OC).

I also have irst installed but no stutters.

10 hours ago, Pe11e said:

 I think I solved massive stuttering with the NGXu and other most likely other CPU intensive addon aircrafts.
 

Sorry, you didn't solve anything. Because if, indeed, you did, Microsoft and every other addon developer would hire you. 

I wish people would stop posting "voodoo fixes" that do more harm than good, especially when the advice is to uninstall another program. 

The only tried and true method is to reduce your settings, or to throw money at the problem and upgrade your hardware, until you reach the point of diminishing returns. 

 

I’d wager it was the Precision XOC Server.  There’s always been problems with the OSD function in XOC (randomly starting in the background or randomly enabling on the screen) which is known to inconsistently cause stuttering in some games on some systems.

Edited January 31, 20206 yr by CaptKornDog

12 hours ago, Pe11e said:

I was also testing performance settings in the NGXu FMC, and found that PFD and ND set to -- (00) it's far the smoothest

 

Thank you. This suggestion definitely made a difference.

9 hours ago, Ricardo41 said:

Sorry, you didn't solve anything. Because if, indeed, you did, Microsoft and every other addon developer would hire you. 

I wish people would stop posting "voodoo fixes" that do more harm than good, especially when the advice is to uninstall another program. 

The only tried and true method is to reduce your settings, or to throw money at the problem and upgrade your hardware, until you reach the point of diminishing returns. 

 

First of all I'm posted my findings what helped me to get rid of stuttering. Maybe few other users will benefit too.

I don't have a need to upgrade my system, 8086k locked at 5ghz and gtx1080 8gb really are enough for me to fly at 38fps locked (half of 75hz). I've see fps drops below 38 only with NGXu, so as I said, someone will maybe find this post useful.

My settings are on medium/high, nowhere near maximum.

Thank you Pe11e for sharing your findings.

eVGA's Precision XOC/X1 utility has been a known problem child for a few years now...pretty much from the release of the 10xx series boards onwards.  Their forums are chock full of unhappy campers, and they've still not figured it out.  If you watch XOC using Process Monitor or Process Lasso, it uses way more CPU resources than a minor utility like this should...I've seen it spike to over 15% of total CPU utilization.  The OSD functionality, as Kyle pointed out, is inconsistent and known to cause performance issues in 3D games (when it works, which isn't often).  I usually have to stop it and restart it manually, then cycle the OSD off and back on to have a fighting chance of having the OSD up when I start the sim.  I've also found that forcing a process affinity on it (to the last two cores) helps keep it from bothering P3D.

So, that said, I don't doubt that shutting it down may very well get rid of some performance issues, even in absence of a Ouija board or a voodoo doll...