Parallels fails to run Flight Simulator - how to remove memory limit?

J

JonathanK8

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SYSTEM SETUP:
Parallels Pro v16
iMac i7 3.8GHz 8 core, 72GB RAM
GPU AMD Radeon Pro 5700XT, 16GB RAM
Windows 10

SOFTWARE TEST:
Microsoft Flight Simulator (MSFS) 2020

PARALLELS - Fail

QUESTION/SUGGESTION - Parallels standard limits the RAM available to the Windows virtual machine. After chatting with your tech support guys, I upgraded to Parallels Pro which removes this RAM limitation. I can now allocate plenty of RAM to the VM... but it appears that I can only effectively allocate max 2GB RAM to my graphics cards, which has upto 16GB available.

With Parallels Pro, I used to be able to start and run Microsoft Flight Simulator (MSFS). Until last week.

The problem is that Microsoft/Asobo issued a patch last week which 'enhanced the clouds'. This update triggers low end graphics cards (the ingame zendesk team specifically mentions the Nvidia 7XX series) to flash any clouds on and off at about 2-5 times per second. Great if you want to experience epilepsy. Not so good if you plan on enjoying the game without a headache.

How do we enable Parallels/Pro to access the full facilities of the GPU? It has 16GB RAM (and is listed as 'ideal' on the game tech spec requirements) so Parallels' 2GB limit is really troublesome...
 
Hi Jonathan,

Please set the video memory option in VM configuration to Auto, it will then allow Windows to use up to half of RAM allocated to VM. If you have 32GB allocated for Windows, then 16GB can be used for video purposes.

No Mac application has direct access to GPU memory or its allocation.
 
Hi again @alev, ok, as you recommended I switched the Hardware/Graphics/Memory option to 'Auto (recommended)' and significantly increasing the Hardware/CPU & Memory resources available to Parallels, to 8 processors and 48GB. The MSFS game runs fine in clear skies. But as soon as clouds are seen, the clouds flicker on and off, at 2-5x per second.

Question: does Parallels utilise my GPU? it's a high end Radeon 5700XT, which has no difficulty handling MSFS, even on Ultra settings, using Boot Camp.

MSFS explain that the flickering or flashing clouds problem began last week, and only affects the (now rather old) Nvidia 7XX graphics cards. If Parallels is employing a virtual simulator of a 7XX GPU, instead of addressing the machine's own graphics card, this would explain the issue.

The solution would be for Parallels to update its GPU simulator to a newer chip. The 7XX is very old now...
 
Thanks JonathanK8 and alev for your feedback
I have read and tried all the suggestions
above and i cant get MSFS to even play
MY SYSTEM SETUP:
Parallels Pro v16.1.1 (49141)
iMac i5 3.GHz 6-Core, 32 GB 2667 MHz DDR4
GPU AMD Radeon Pro 580X 8 GB
Windows 10 Pro

SOFTWARE TEST:
Microsoft Flight Simulator (MSFS) 2020

PARALLELS - Fail

QUESTION/SUGGESTION -
The settings for CPU & memory. AND Graphics are shown below. Ive checked all that was suggested above

Screen Shot 2020-12-14 at 9.09.03 pm.png

Screen Shot 2020-12-14 at 9.10.22 pm.png
 

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MattF6 said:
Thanks JonathanK8 and alev for your feedback
I have read and tried all the suggestions
above and i cant get MSFS to even play
MY SYSTEM SETUP:
Parallels Pro v16.1.1 (49141)
iMac i5 3.GHz 6-Core, 32 GB 2667 MHz DDR4
GPU AMD Radeon Pro 580X 8 GB
Windows 10 Pro

SOFTWARE TEST:
Microsoft Flight Simulator (MSFS) 2020

PARALLELS - Fail

QUESTION/SUGGESTION -
The settings for CPU & memory. AND Graphics are shown below. Ive checked all that was suggested above

View attachment 17021

View attachment 17022
Click to expand...
Hello Matt. I have almost the same computer as you (but less ram and may graphics card is 570X 4GB).
I'm just curious if you found a solution to this. I am planning to buy MSFS if I can run it on my iMac.
So did you use Parallels after all or maybe using BootCamp?
And what type of joystick is working on Mac with MSFS?
 
I tried Parallels 17 (related to Bootcamp) and in Flight Simulator 2020, some images are strange. Clouds for example. I think it does not use the capacity of the graphics card (radeon PRO 5500 XT 8 GB). That's why I'm not buying Parallels right now while waiting for a solution.
 
I wouldn't play this game with Adaptive Hypervisor on. The overhead is noticeable.

Back when I was playing it on very underpowered hardware (Mac Pro 2013 with 12 cores), I strangely found that limiting the CPUs to 4 was better than more. Weird little things like that -- but more RAM always helped (whether allocated RAM, physical system RAM or physical GPU RAM installed on an eGPU).

Also I set for "Best for External Displays" but that's hard to explain. You have to use "Full Screen" mode in the game itself -- the key is not to be wasting pixels somewhere along the way. I'm tinkering again with "Scaled Mode" as we speak, but I'm certain that the default choice of "Best for Retina Display" worked really badly for me in my early days of tinkering around. It's possible that I hadn't discovered the "Full Screen" mode though, since playing it "Windowed" always forces the game to render in the number of pixels that Windows believes it has -- and that could be MANY, when you're in Parallels. So tl;dr please use "Full Screen" in the game's General Settings.

One other tip is to put "Off Screen Terrain Pre-Caching" to minimum. Anything else never seems to help.
The only things that truly drive game performance seem to be raw resolution, Render Scaling and Terrain Level of Detail.
Everything else seems more or less irrelevant.

Just recently I've started running the game on a display set to 24fps via a TV, and letting it use Soap Opera Effect to push to 60fps. Marvellous.
 
Christian63 said:
I tried Parallels 17 (related to Bootcamp) and in Flight Simulator 2020, some images are strange. Clouds for example. I think it does not use the capacity of the graphics card (radeon PRO 5500 XT 8 GB). That's why I'm not buying Parallels right now while waiting for a solution.
Click to expand...
Hi other Christian, yes I found the same once I switched from an old FirePro (vintage 2012) to a 2020+ era AMD card (5700 or 6900). Seems like a bug in Flight Simulator because it happens in Boot Camp too, BUT, you won't be aware of it if:
  • the clouds are fluffy enough, or,
  • you are using a high enough combination of Resolution + Render Scaling + Volumetric Clouds.
But even with Volumetric set to Ultra, resolution set to 4K and as much Render Scaling as possible (e.g. 100), and reducing other graphics settings to compensate, and not being too fussy with frame rate, it's sometimes still possible to see clouds get stripes in them when they're wispy. After levelling up my GPU skills 2 or 3 times, I still haven't found a way to overcome this fully or "disable" the issue, and I am currently convinced there's no single setting to work around it.

For now I recommend this for MSFS 2020 Flight Simulator:
1. Same top settings as Boot Camp; if your card can handle 4K then it won't improve at 1440p or 1080p. Full Screen, TAA, Scaling 100, FidelityFx 200, V-Sync On, 100%, DX11.
2. Choose a Global Rendering Quality then make the tweaks below. For Parallels I choose "Low", Boot Camp is 2 settings up at "High".
3. The following tweaks improve the results over the presets noticeably, without lowering frame rate:
  • Volumetric Clouds = Ultra
  • Texture Resolution = High
  • And probably Off-Screen Terrain Pre-Caching ... reduce to Low, actually improves performance with no side-effect IMO, YMMV.
Probably restart the app for a proper assessment.
MSFS even gives a warning for tweaking Texture Resolution without restarting, but there's a bug since it doesn't warn if you change that setting via a preset, yet still warns you if it hasn't changed after a preset choice plus making the individual setting the way it was before.

Since you're restarting the app, might as well shut down Windows to check your Parallels settings:
  • DISCONNECT OTHER DISPLAYS -- this is the biggest one. Your GPU struggles when it has all those external monitor pixels.
  • CPU: I'd just give 75% of them, though on a 2013-era Mac I found it better to lower it to 4 out of 12
  • Memory: Again 75% of your Mac's. Windows might not use it for a while, but it will.
  • Extended memory limit must be Off
  • Hypervisor must be Parallels. If you can't install it or make it work, I found a fresh macOS install of Sonoma fixed it.
  • Adaptive Hypervisor must be Off
  • Nested Virtualisation must be Off
  • Graphics: probably "Scaled", particularly on a 5K or 6K Mac. Tell Windows Settings to switch to 3840x2160 and check on it daily.
    You could try "Best for external displays" too but never use "Retina display".
    While you're figuring it out, Windows gets stupid and increases font size. Just put it back to 100% asap (maybe 125% first then 100% again).
  • Keyboard & mouse optimized for games (but learn how to get out of it before you get trapped).
    Getting rid of needing the 'Fn' key is also a choice. Most people probably want it, but it depends if you multitask.
    I find MSFS 2020 is more of a screensaver than a game.
 
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