PSA: NVidia has found the root cause of stuttering and VR performance in their drivers!

This is expected: one HT processor is not a full core. HT is a technology which permits “splitting” the instruction stream in a way which minimizes contention. If you do have a series of instructions and one takes a longer time, the code won’t make any further progress during this time. With HT, some instructions can therefore run in parallel and it usually is effectively raising throughput by 5% on average and about 15% max.

However, should the thread scheduler uses the 2 HT units of the same core for 2 different threads, any synchronization between the 2 threads will effectively renders HT useless. Furthermore in this case, because the cache lines are shared, you can have other side-effects effectively reducing the throughput. This is why when you’re implementing a work task scheduler (see Intel TBB for example) you have to pay attention to this and effectively ‘pin’ your work task scheduler threads to “main” core only (i.e. CPU0, CPU2, CPU4, CPU6 etc…) for better results.

The issue is Win32 API presents these HT cores as if they were 2 real independent CPU cores which is not true, and it takes special care to manage these efficiently.

This is why in general for gaming, CPUs without HT are better (or disable it in the BIOS) and for flight simulator (not flight simulation) single core performance is key to choosing a CPU brand/model.

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Understood, thanks for the explanation.
I thought about turn it off for some times ago, as I also discovered last summer when I upgraded to the 10700K that my CPU is easier to OC and stay cooler with HT OFF. HT at least for gaming it’s useless nowadays…

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Just wanted to give an update. I tested 461.33 again and turned off Hardware Accelerated GPU Scheduling in Windows, and I am now getting the same frame rates as I was getting in 457.30 using my G2 with Windows Mixed Reality.

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So, if I’m still using 457.30, should I enable or disabled Hardware Accelerated GPU Scheduling? Will not put 461.33 back in until I’m sure. It messed everything up

I’ll be honest guys, I, like others appreciate the effort in getting this figured out but most of this is over my head. I don’t have the time to sit and learn a bunch of computer stuff. Right now, I have NO IDEA what driver to use, what settings are WHERE and how to change a bunch of stuff. I’m not computer stooopid but dang close.

System Specs:
Power Supply: Corsair RM850X
MB: MSI Gaming Pro Carbon
DUAL 2GB NVMe Drives. One in TURBO M.2 slot.
CPU: Intel i9-9900KF 3.60 ( I overclock MSFS2020 to 4.8 when possible.)
RAM: 32GB Corsair RGB RAM (No O/C of RAM)
Windows 10 64
GRAPHICS: nVidia GeFORCE RTX 2080 TI
Res: 2560X1040 (144Hx)
Dual DELL S2716DG Monitors.
Onboard Audio.

I believe you’ve forgotten to add your headset in the list?

Don’t look any further, this could give you a good start:
My 2070 SUPER VR settings and suggestion (Reverb G2 - WMR)
My 2070 SUPER VR settings and suggestions (Index - SteamVR)

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Headset is a INDEX. Sorry! I have read the posts as much as possible however it is a lot to digest. there is 428 posts talking about tons of stuff. I just tried the 457.30 driver along with the SteamVR BETA and it tanked my sim. Totally unflyable. Not sure what to do now.

There is a long discussion of interesting topics and developments on the subject of VR where a lot of people can learn and better their experience!

Nevertheless, why not just starting with the 1st post only…

Again Cpt, I’ve read as much as possible. Over and over. Seems there are a million different setups. Will relaod the latest driver again and see what happens.

@RwpTurnip, I concur with @CptLucky8. Just go to post #1, do exactly what it says, and don’t worry about all the details. Step by step, just follow the instructions.

That’s what I did, and it worked quite well. But I’m a tweaker by nature, so I’m still tweaking lol… And in the meantime I keep reading the detail stuff slowly, so I can actually absorb what is being said, and it’s (very) slowly starting to make sense to me in such a way that I can do more than just follow step-by-step instructions.

But start with that, it’ll fall into place eventually.

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I have to say, after a few hours of flying in a mix of cities, mountain & desert terrains, I am finding the 461.33 driver with SteamVR 1.16.2 & Valve Index to be the smoothest experience I’ve had yet in this sim in VR. I also currently have HAGS enabled, and I’m not getting any stuttering whatsoever (although I don’t know if I see any difference in framerate + or -).

My CPU is i7 9700K @ 4.9 GHz, with RTX 2080 Super.

This is now performing well enough for me to where I’m ready to quit tweaking and just enjoy the sim for awhile. :slight_smile:

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That’s good.

I tried the G2 on 457.30 with the latest steam OpenXR runtime and now it gets actually marginally better perf than using the WMR runtime for me, previously it was worse.

Switching to 461.33 works well in my steamVR games I’ve tried so far, but turns msfs into a stutter mess again (using steam openXR at least, didn’t have time to test it on wmr version).

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Quick question - do you notice any change in your head movement in the cockpit when using Steam OpenXR runtime vs. Windows OpenXR runtime?
To not derail this thread, please check out here: Bobbing (Tilting) head up and down in cockpit view (plane's dashboard goes up and down) - #17 by PolackofDoom

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I have Nvidia 461.09 installed (is this good or bad?) And GeForce experience tells me that it is the latest driver. So, how can I get my hands on 461.33 that everyone here is talking about?

GFORCE does not update HOTFIX Driver like 461.33, suggest you use GeForce 461.33 hotfix driver download (guru3d.com)

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I’d suggest you download anything NVidia from the NVidia website only:

GeForce Hotfix Driver Version 461.33 | NVIDIA

PS: by the way, this link is already posted in this discussion. Search is your friend…

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For the moment 457.30 is the best driver for me with MSFS2020 but with other games it not hte best… The 461.33 is a stutter mess with OXR. NVIDIA need to fix the stutter with OXR

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461.33 seems to work even better for me than 457.30 at least when using Virtual Desktop with the Quest 2 (using SteamVR instead of Oculus). I also noticed lag and stuttering when approaching any airfield, turning off all types of airport traffic/people (but I also turned off all other traffic like road traffic and sea traffic) seemed to get rid of that. I can now get a pretty smooth flight with quite high settings in an aircraft without glass instruments.

Anyone here has tried 461.33 and Geforce experience? I know it is advised everywhere to remove Geforce Experience while using VR and that’s what I did when I rolled back to 457.30, uninstalling GfE, but I really miss GfE. I was using it a lot when I was flying in 2D (color and exposure tuning, capturing 32 bits HDR screenshots, video recording), in 2D, it had no impact at all on my FPS count.
Right now I am satisfied with 457.30 but if 461.33 allows to use Geforce experience again, I’m in !

I would hope there’s further optimisation to come from Asobo themselves, having done a lot of Benchmarking recently it’s very evident that there’s plenty of room for improvement. Here’s a list of my findings that all point to the need for this to be looked it (if not already with the upcoming next update…fingers crossed):

  • Two identical Sessions can have differing results; by this I mean when I do my Benchmarking I always do it on the First Run of MSF after a clean PC Reboot. Sometimes I get into VR on the Runway and the FPS is at 30ish, the next time I do it it’s at 25 yet both scenarios are identical (same weather, time of day, Data settings etc)

  • Switching from Pancake to VR Mode can sometimes take a while for the FPS to settle down, other times it’s just fine straight away. It’s like VR Mode is taking too long to Register and you end up sitting in the Plane waiting for things to settle down.

  • Likewise switching from Pancake to VR Mode the FPS/Frametime is atrocious and giving it time does not help, an exit of the Sim and reboot of the PC is needed even though this was after a clean reboot.

  • Fly above the Atlantic in Clear Weather with AP On and watch any Performance Graph like MSI Afterburner or CapFrameX or FPSVR, you’ll see random drops on FPS for seemingly no reason whatsoever which suggests something is at play. Edit: just to add to this point, turn off all background tasks especially GPU/CPU monitoring type software and you’ll still see the effects of random FPS drops.

Add to that the latest nVidia Drivers are not exactly helping matters (even with the smoothest, for me, 457 can have issues), the OpenXR Platform is very bare/basic and still relatively new, plus SteamVR has a history of sporadic behaviour and you end up with a mix of various variables that can play into an unstable simulation.
For sure MSF2020 is not totally at fault due to those other areas, but it’s clear to me there is still some way to go to get this Sim running correctly, regardless of the other programs/drivers.

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