Desktop Window Manager (DWM) memory usage extremely high

Bug Reporting Hub Hardware & Peripherals
1

Hello all,

I’m at wits end with an annoying problem. Hopefully someone can shed some light on it.

I have a brand new gaming laptop, with an i7-10750 6-core CPU, 32 GB DDR4 ram, and Nvidia RTX 2060 GPU with 6bg of memory. Two 1TB M.2 NVMe SSDs. Windows 10 is at 20H2 update, and all firmware and software up to date.

The problem is the Desktop Window Manager (DWM, as seen in the processes tab of task manager) will pretty rapidly (within 10-15 minutes) climb from a normal 108-200 mb of memory usage, to insane percentages of memory. I flew for 45 minutes the other day, and it had 7 GB (yes, GB, not MB) of memory used for DWM. Once quitting MSFS2020, it does not continue to climb, but also will not go back down.

I did some investigating and found it’s ONLY MFSF2020 that causes this, and only when the ATC window is on my second monitor. I have two screens, so why not put that window on the second one, I thought… Well…I guess it causes problems.

I have tried the following to remedy this.

-Updating windows from version 2004 to 20H2.
-Updating Nvidia drivers from 456.xx to 460.89
-Running integrity check on RAM
-Running windows diagnostics
-Running full virus scan with my A/V and from Eset online
-Running MS System File Checker (sfc scannow)
-Changing Virtual Memory Paging size to recommended size vs. auto managed size.
-Contacted laptop manufacturer (they had no idea)
-Contacted Microsoft (they had me do the same basic things I’ve already done)
-Lots of googling.

Seems like a common problem, but no clear answers.

The real kicker is that it doesn’t always have this issue. Some days I can fly with the ATC window on my second monitor and DWM will sit happily at 108mb the whole flight. I change nothing, boot up the next day with all the same settings and same running software, and it will chew through gigabytes of memory.

The ONLY solution I’ve found is to not put the ATC window on the second screen. Which then defeats the purpose of having two screens. Not ideal at all.

Thank you for any help!

2

I’m not going to be much help, probably more the bearer of bad news.

Laptops work differently than PCs do. Even though there’s an additional graphics card, the integrated graphics card still works as the “pass through” for all video back to the main desktop UI from the dGPU. This is the job of the DWM process, in charge of drawing what’s on the screen.

The reason why MSFS is different, is that those pop outs are basically web browsers. As to why they climb up in utilization, my guess it has something to do with the way MSFS wrote (or borrowed) the HTML rendering code.

I’m on a gaming laptop and see these issues too. The only advice I can give is to use third party simmconnect apps to show whatever you want to see.

Edit to add, I don’t there’s a way to have a non-MSFS based interface into ATC. ■■■■.

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Hmm… I wonder if that’s why we are getting these mysterious CTDs? Using the ATC window. I remember the last time I CTD, I was flying over the NYC/Wash DC area and getting a frequency change every 5 minutes.

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Thanks for that insight. If that’s it, it’s something that can be managed. My main concern is that there’s something wrong with my new system. If this is just a consequence of a laptop gaming system, then so be it I suppose. I’ll just log out/log in of Windows when it becomes a problem.

I’m still thinking/hoping it’s a bug with Windows 10 or MSFS or the combination of those two because if I have a web browser open on the other screen, or sim management programs, or NZXT’s system monitor, but… not the MSFS ATC box, this issue does not occur.

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In fact, here’s some new info, I just ended the DWM process and let it auto-restart, and the issue appears to be gone again, through several restarts of the computer and test sessions of MSFS.

Very odd…

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Yeah - I think you have a bug with MSFS. If you’re able, file a bug report with your findings. Definitely not normal behavior.

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7

I just did the same flight going over the same area that I CTD before, except without responding to any freq handoffs. Made it all the way. Nothing but the usual AP stupidity and some really turbulent wx from the cold front across the east coast.

You may be on to something here. I would submit a bug report.

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8

I believe this issue is an Intel HD one where laptops have a gpu and Intel hd. There is a post on Intel forums about a dwm.exe memory leak. I have sent Intel a lot of data but they are yet to fix it. Just end the dwm process when ram use gets above 100-150mb. Sometimes mine goes to 5gb!

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9

Very interesting! I’ll file a bug report on Zendesk anyway - might help.

Yep - ending the process seems to work. At least temporarily. For a few flights/launches of FS. Then it comes back randomly.

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Not sure how you class that as high, here is a screenshot of my task manager memory usage all I am running is the skygo tv app.

It’s normal to see 18 + gb’s memory usage while using msfs with 32gb ram.

Desktop Screenshot 2020.12.25 - 03.47.52.23
Desktop Screenshot 2020.12.25 - 03.47.52.233840×2160 171 KB

From what i read about this there is no need to edit this these days especially with 32gb’s of ram.

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You’re 100% correct that the overall (Windows + MSFS) memory usage can and often is in the 16-20 GB range, but what we’re speaking about here is DWM.exe, a Windows background process, that sometimes decides to leak an additional 500mb to 7 GB of ram. So in your case, it might show 15 GB in use, but only 8.3 would be doing anything productive.

I agree with you that the page file should not need to be edited, but this was at the direction of MS support. Apparently the more memory you put in a computer (going from 16gb to 32gb, for example), the page file will actually increase, which is somewhat counterintuitive. I found that when mine was set to “system managed,” it was actually at 13 GB, which is way overkill. Even though the “system recommended” value was around 4GB. I’m probably never going to max out my 32gb of RAM, so I set it to the recommended value. No idea why the system managed setting was so much higher. A benefit is that I gained back 9 GB of SSD space.

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12

I did some research and it seems this is indeed an Intel chipset issue that is plaguing many new Windows 10 machines. Some newer firmware seems to have the issue, the older Intel firmware doesn’t. Many people don’t realize the memory leak is occurring and when the computer gets slow, they just restart it. I’ve found a good way to reset DWM.exe when this happens. One example of a command line restart is here (for Windows 8, but applicable for 10 too): https://superuser.com/questions/656162/windows-8-restart-desktop-window-manager

There’s also talk about rolling back to an old version of the Intel driver which will also fix the issue: https://answers.microsoft.com/en-us/windows/forum/all/desktop-windows-manager-dwm-memory-leakage-in/c2968fb0-ee26-4483-9f08-dfa19149cd24?page=1

But it seems there were security concerns with it, and I’m not sure I want to take that chance. So…

I’m trying a batch file with this code set to run when Windows starts - will let you know how it goes. Hopefully Intel can patch this soon.

1 Like
13

Please check your system with
mrt and sfc /scannow (in cmd)
to be shure there is no problem with installation and malicious software

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All good ideas, but as stated in the first post (and discussed in subsequent posts) these have already been run and found nothing wrong.

This appears to be an Intel issue that is affecting a wide range of computers.

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There are some reports about, e.g.

Isn’t it possible to disable the usage of Intel GPU in BIOS ? I assume the laptop is mainly used at a power supply.

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Interesting idea. I’ll look into it. Though restarting the dwm.exe service seems like a less invasive fix, assuming that Intel eventually finds a permanent fix for it.

It seems like (and this is just me speculating) this all came about after they tried to patch a security vulnerability, because reports seem to indicate that drivers prior to April 2020 or so did not have the memory leak issue.

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