Random, unexplained performance drops--PLEASE target this ASAP!

When I say ‘unexplained’ I’m referring to when suddenly, out of nowhere, in seemingly non-complex areas while flying, sudden frame rate drops occur causing complete disruption of smooth flight–and that’s AWFUL in a flight sim. To expand on this more this is happening when realtime CPU and GPU monitoring shows lots of headroom in both, and further server access time is at default which for me in the midwestern US is around 42ms. Right now, just west of Denver well over the rockies and very little roads/buillding, my vsync to 30Hz when always insures a solid frame rate of 30 UNLESS GPU or CPU utilization is approaching 100%–that is NOT THE CASE as right now GPU load is around 65% and CPU around 70%. Please address this it really is not something to ignore.

Thanks

I had a similar experience, closed everything down ran Taskmaster and discovered a that couple of programmes unknown to me were running in the background.

Try to disable the VFR map from the top menu settings. Closing it is not enough, you have to completely hide it from the top menu. This usually helps.

As for CPU and GPU utilization. I also had that issue where the FPS counter from the Dev Mode is telling me I’m Limited by main thread. At that time I was running at 10-15 FPS on Lowest settings, and I’m on i9-9900K, RTX 2080 Ti, and 32 GB Ram.

So I went to my motherboard BIOS and I disable Hardware Virtualization Technology and VT-d. Then I run MSFS again, and now I can fly at stable 30 FPS on ULTRA. And the FPS counter no longer says I’m limited by Main Thread, now I’m limited by my GPU but my GPU utilisation almost 100%, so that’s fine.

Note that VT-d and virtualization being enabled or disabled should not cause a massive performance change. Normally if any difference it would be small, like a fraction of a percent, due to additional overhead if and only if the operating system has virtualization / hypervisor enabled (which it does not by default).

So if you’re seeing a difference with it on and off, that’s surprising.

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It helps if you only have 4 cores and hyperthreading to 8. Maybe even 6 cores need to be hyperthreaded to 12. Beyond that, I agree, it doesn’t help.

I appreciate the suggestions thanks. it’s very hard to nail down why this happens because it’s so random. There is some tendency to reoccur in the same geographic areas, but not always. I can be in the most visually complex areas and this does not occur, then be in a nothing burger rural area and it presents. Because I vsync to 30Hz it’s very easy to see when output becomes GPU limited, and therefore easy to adjust sliders accordingly, which is not the case otherwise. CPU and GPU and server access time seem to have nothing to do with this behavior. My sense is perhaps it’s attributable to server load at that moment in time, so is remote to our hardware per se. I’d really like Asobo to focus on this because it affects most users, most likely, so please vote this topic up else it will left to various guesses. If the VFR map is a culprit sometimes, they need to know this so that can be addressed, for example. I don’t have hardware virtualization enabled and Dev Mode always states i’m GPU limited, though as I say I can adjust out of this–the problem is that strategy does not work with the issue I’m describing as I can adjust GPU intensive sliders down so I only show 50% utilization, and still this strikes.

AGAIN: please vote this else it will be left to inside guesses.

I know, it is surprising, While yes, Hyper-V is disabled by default in the OS. Hardware Virtualization Technology is enabled by default on the BIOS level. (At least that’s how it was on my motherboard). I know because I flash my BIOS firmware very frequently, as soon as they release a new firmware BIOS version. After that I always reset all BIOS settings to its Factory Default values. And the Hardware Virtualization Technology setting is always enabled on Factory default setting. I usually leave it alone since that’s just how the factory default setting is.

I’m not even doing any virtualization on my own, like I said, I don’t have VMs running, my Hyper-V is disabled as it is by default in Windows 10.

I’m with you here, it’s surprising, it doesn’t make sense, and it shouldn’t help at all. Yet the result speaks for itself, when I leave it on default, (HVT enabled, Hyper V disabled) I’m getting low 10-15 FPS with Limited by Main thread at any graphics setting level. Once I manually disable HVT on the BIOS, making me set it away from the factory default setting, my fps jumps to stable 30 FPS on ULTRA, while I can push more than that on lower graphics settings, with overall bootleneck to no longer be Limited by Main thread but Limited on GPU.

I didn’t find about this “workaround” myself, I wouldn’t even think about this since like I said, before I install MSFS I reflashed my BIOS, clean install Windows 10 (as it was just released 21H1 version), and I kept everything at their factory default setting. But I’m getting low FPS, until I stumbled upon this “solved” topic, which suggest to disable the HVT on the BIOS. I merely follow the advice, and by some miracle that makes no sense, it does help my performance, as it did help on their performance issue in that topic.

That doesn’t make sense. You can’t increase the number of cores by virtualization.

Are you thinking of hyperthreading? That also should make very little difference, but it’s unrelated to VT-d and virtualization.

Hey it’s the weekend, I’ll give it a whirl myself and see if it helps. :wink:

(I have it on for WSL2 but can disable it in a pinch on this machine.)

[Update:] Made no visible difference in my testing. Flew C172 steam gauge from KSFO up the peninsula, buzzed downtown, circled west past the north waterfront then came around to buzz through downtown and then low over south of market.

At ‘ultra’ settings this is mostly evenly matched between main thread times and GPU times, and one or the other may dominate from moment to moment. Usage of both goes up, but slightly more for CPU, directly over downtown with the maximal number of high-res buildings loaded up.

Tried these three scenarios on Ryzen 7 3700X:

  • WSL2 enabled (so hypervisor and virtual machine platform enabled in Windows, and SVM enabled in BIOS)
  • SVM disabled, but WSL2 deps still installed thus non-functional
  • SVM disabled, and also uninstalled hypervisor and virtual machine platform in ‘Windows features’

All three look like they give me the same performance profile; I start around 25-28 fps on the ground, climb up to 35-38 fps as I reach the hill south of the city, then slowly down towards 30ish around downtown. Dips below 30 here and there as low as 24 fps as performance fluctuates on both GPU and CPU, with highest CPU usage on the low-altitude passes on downtown and South of Market.

FWIW, I just landed at KPHX from KBJC, lots of air traffic upon arrival, and plenty of CPU/GPU headroom, and yet lots of FPS drops from my steady 30 down to low 20’s up again, back down etc, causing severe stuttering.

I just took off from KPHX to KBJC in the same plane, same traffic, liquid smooth. The difference? Went to Dev Mode at the start of the flight, cleared the console of errors/warning/messages, then disabled Dev Mode and proceeded. Of course, I did not see the spinning indicator of console logging. The downside of this is when you go into Dev Mode within a flight, you will no longer see the flight logged into the Pilot Logbook. See my other thread this is a major issue and may be tied to the one at the start of this thread, random perf drops:

Oops, you’re right…I mixed up hyperthreading and virtualization. Turn Virtualization Off for better performance, I agree.