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Can someone explain what values to put for Multimedia Class Scheduler for gaming?

zaza

Member
Feb 11, 2015
130
1
0
I want to improve realtime gaming performance.
In the registry (in HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Multimedia\SystemProfile\Tasks\Games) there's these two value for example:
Priority
Scheduling Category

According to Microsoft:
Priority: The task priority. The range of values is 1 (low) to 8 (high).
For tasks with a Scheduling Category of High, this value is always treated as 2.
Scheduling Category: The scheduling category. This value can be set to High, Medium, or Low.
So according to Microsoft, a high Scheduling category gives a game a low Priority? Cause they said that "For tasks with a Scheduling Category of High, this value is always treated as 2." I'm confuse. What should I do, set the task priority as high (8) or set the scheduling category to high?
 

Borealis7

Platinum Member
Oct 19, 2006
2,784
122
106
is there any evidence that changing these settings improves performance?
typically, you shouldn't be messing with the Windows task scheduler priorities, the kernel does that for you.
plus, you are probably more GPU bottle-necked in games than CPU-starved. giving a game more CPU won't necessarily give you more performance.
 

zaza

Member
Feb 11, 2015
130
1
0
is there any evidence that changing these settings improves performance?
typically, you shouldn't be messing with the Windows task scheduler priorities, the kernel does that for you.
plus, you are probably more GPU bottle-necked in games than CPU-starved. giving a game more CPU won't necessarily give you more performance.
That's very nice.


...


Now about the question
 

Markbnj

Elite Member <br>Moderator Emeritus
Moderator
Sep 16, 2005
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www.markbetz.net
That's very nice.


...


Now about the question
He answered your question. Farting around with the scheduler registry entries will not improve your game performance.

What you want is Magic Registry Driver Sweeper Cleaner. It's made by some Chinese company. Run it once and all your programs will be faster and your carpet will smell fresh as daisies. But I'm sure you already have it.
 

zaza

Member
Feb 11, 2015
130
1
0
He answered your question. Farting around with the scheduler registry entries will not improve your game performance.

What you want is Magic Registry Driver Sweeper Cleaner. It's made by some Chinese company. Run it once and all your programs will be faster and your carpet will smell fresh as daisies. But I'm sure you already have it.
How did you become a moderator?
 
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Gryz

Golden Member
Aug 28, 2010
1,551
203
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By being to the point maybe ?

I'm gonna be the third guy here telling you: don't mess around with stuff you don't understand. In this case, don't mess around with the scheduler.

Scheduling priorities do not give your PC more CPU power. They will only make sure that when there's not enough CPU power, some programs will be prioritized over others. But those programs will still not get magically more CPU than you actually have.

In stead of messing with the scheduler, a smarter way to achieve the same thing would be to make sure you don't have any programs running when you play games. So quit your web-browser. Close your Skype. Close all utilities you have open. Only run your game. That will probably help with memory usage as well. The effect would be better than configuring a registry entry for the scheduler could ever be.
 

zaza

Member
Feb 11, 2015
130
1
0
By being to the point maybe ?

I'm gonna be the third guy here telling you: don't mess around with stuff you don't understand. In this case, don't mess around with the scheduler.

Scheduling priorities do not give your PC more CPU power. They will only make sure that when there's not enough CPU power, some programs will be prioritized over others. But those programs will still not get magically more CPU than you actually have.

In stead of messing with the scheduler, a smarter way to achieve the same thing would be to make sure you don't have any programs running when you play games. So quit your web-browser. Close your Skype. Close all utilities you have open. Only run your game. That will probably help with memory usage as well. The effect would be better than configuring a registry entry for the scheduler could ever be.
You are so smart! Thank you! God bless you!
Now back to the question, does anyone know which values mean what?
 

chimaxi83

Diamond Member
May 18, 2003
5,648
61
101
Why do you want to improve real time gaming performance? Are you gaming on a toaster?
 

Fox5

Diamond Member
Jan 31, 2005
5,957
7
81
I want to improve realtime gaming performance.
In the registry (in HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Multimedia\SystemProfile\Tasks\Games) there's these two value for example:
Priority
Scheduling Category

According to Microsoft:



So according to Microsoft, a high Scheduling category gives a game a low Priority? Cause they said that "For tasks with a Scheduling Category of High, this value is always treated as 2." I'm confuse. What should I do, set the task priority as high (8) or set the scheduling category to high?
I read it as:
Task priority ranges from 1 (low) to 8 (high). However, the scheduling category overrides this, so that if scheduling category is High, then the priority value is set to 2.

That said, I find it highly suspect that there would be one overriding registry key that would effect the priority of all games. How does Windows know what is a game or not?
Secondly, you could very well hurt gaming performance by increasing the priority of games, locking out other Operating System tasks. Games should be relatively low priority BECAUSE they tend to consume 100% CPU time. If you set them to high priority, nothing else will run and your system will lag, including the game as it waits for the OS to complete operations.
 

zaza

Member
Feb 11, 2015
130
1
0
I read it as:
Task priority ranges from 1 (low) to 8 (high). However, the scheduling category overrides this, so that if scheduling category is High, then the priority value is set to 2.

That said, I find it highly suspect that there would be one overriding registry key that would effect the priority of all games. How does Windows know what is a game or not?
Secondly, you could very well hurt gaming performance by increasing the priority of games, locking out other Operating System tasks. Games should be relatively low priority BECAUSE they tend to consume 100% CPU time. If you set them to high priority, nothing else will run and your system will lag, including the game as it waits for the OS to complete operations.

It knows it's a game because most games have the function called in their code. "A thread must invoke MMCSS explicitly to use its services by calling the AvSetMmMaxThreadCharacteristics()"

I know most if not all games use it cause it's a common registry fix for ping spikes in online games to increase the MMCSS network throttle index value, which is the limit on the number of packets that can be recieved.

And high priority does not harm game performance since high priority is still always below crucial system tasks' priority. According to Microsoft: "These threads run at a thread priority that is lower than only certain system-level tasks. This category is designed for Pro Audio tasks."
 
Last edited:
Feb 4, 2009
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Stuff like this may have worked in 1996 but now yours CPU is so stupidly powered that there is no point except risking screwing up windows.
 
Last edited:

TheVrolok

Lifer
Dec 11, 2000
23,471
2,815
136
I don't know if anyone has offered this opinion yet, but I would recommend against this type of registry tweaking. It is highly unlikely it will provide any significant performance improvement and is more likely to cause issues. Also, being a jerk doesn't help.
 

TheRyuu

Diamond Member
Dec 3, 2005
5,479
14
81
So according to Microsoft, a high Scheduling category gives a game a low Priority? Cause they said that "For tasks with a Scheduling Category of High, this value is always treated as 2." I'm confuse. What should I do, set the task priority as high (8) or set the scheduling category to high?
You have to think of it has a hierarchy. There are scheduling categories (High, Normal, Low, Idle) and each category has different priority levels. So something which is in the High category will always be above something in the Normal category even if Normal has a higher priority (as can be seen here[1], look at the table on the bottom of this page).

The default values that Windows ships with are the ideal values so don't mess with them. Also if all you're doing is playing a game and that's the only thing you're doing then MMCSS won't be doing a lot if anything.

How does Windows know what is a game or not?
You have to specify which MMCSS profile you want to use when you "enable" it for an application (or more specifically the thread(s) you're enabling it on). For example foobar2000 uses the "Audio" profile.

[1] https://msdn.microsoft.com/en-us/library/windows/desktop/ms684247(v=vs.85).aspx
 
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DefaultisNeverBest

Junior Member
Mar 14, 2021
4
1
36
Is this really y'all's advice for this guy? I've never seen such terrible advice in my life. You do realize this is a TECH forum right, so when a person asks a tech question, one would guess (ya think?) that they expect a tech answer; not an answer like "No, don't touch that" or "stick with default" or "windows knows best", lol, wth. Do any of you really have any degree or experience or technology? please shock me.

Okay friend. For the record everyone who responded to you is a PROVEN noob, and this is the evidence:


Go down to "More Gaming Tweaks"

Thank me later. And if anyone ever tells you Microsoft or Windows knows something, or even Apple for that matter, you are not in a tech forum; they are not a tech. God bless.
 
Feb 4, 2009
30,499
11,014
136
Is this really y'all's advice for this guy? I've never seen such terrible advice in my life. You do realize this is a TECH forum right, so when a person asks a tech question, one would guess (ya think?) that they expect a tech answer; not an answer like "No, don't touch that" or "stick with default" or "windows knows best", lol, wth. Do any of you really have any degree or experience or technology? please shock me.

Okay friend. For the record everyone who responded to you is a PROVEN noob, and this is the evidence:


Go down to "More Gaming Tweaks"

Thank me later. And if anyone ever tells you Microsoft or Windows knows something, or even Apple for that matter, you are not in a tech forum; they are not a tech. God bless.
Quite the first post you got there. What brought you to a 6 year old thread about modifying windows scheduler to increase game performance?
What poor advice was give that caused you to create and account then come out guns blazing?
 

DefaultisNeverBest

Junior Member
Mar 14, 2021
4
1
36
Google actually. Well, the "guns blazing" was perhaps a bit much. It's just I found it odd that a legitimate question is circumvented by "I'm sure windows knows best" and all that fluff. Granted, it's a small segment I'm sure and most on here probably are well aware Windows does not know best, but I felt bad that this guy was given no useful answer other than essentially no answer at all.
 
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Feb 4, 2009
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Google actually. Well, the "guns blazing" was perhaps a bit much. It's just I found it odd that a legitimate question is circumvented by "I'm sure windows knows best" and all that fluff. Granted, it's a small segment I'm sure and most on here probably are well aware Windows does not know best, but I felt bad that this guy was given no useful answer other than essentially no answer at all.
Cool, hang around for a while but I advise skipping P&N for your first year.
 

UsandThem

Elite Member
Super Moderator
May 4, 2000
14,729
5,376
146
Google actually. Well, the "guns blazing" was perhaps a bit much. It's just I found it odd that a legitimate question is circumvented by "I'm sure windows knows best" and all that fluff. Granted, it's a small segment I'm sure and most on here probably are well aware Windows does not know best, but I felt bad that this guy was given no useful answer other than essentially no answer at all.
The OP acted like a jerk, and in turn most people didn't want to waste their time helping them for free.

Not to mention, when this was posted Windows 10 was new.
 

DefaultisNeverBest

Junior Member
Mar 14, 2021
4
1
36
lol, I'm sure both of you mean well. I didn't mean to make this thread as exciting as P & N, lol. I was nearly going to edit my original post & make it more friendly.
 

DefaultisNeverBest

Junior Member
Mar 14, 2021
4
1
36
oh, is that where the fun's at? lol. Until you mentioned it, I didn't even know it had a thread. But now I'm curious...this is how u recruit more people to P & N isn't it? lol

PS: Clearly my quoting skills leave much to be desired. I clicked quote from 3 posts above and don't see it.
 

VirtualLarry

No Lifer
Aug 25, 2001
51,356
6,581
126
You want smoother Gaming performance on Windows 10?

Go into Settings, Privacy, and turn OFF all of those "Auto-run apps", that pre-load at Windows startup. That's a lot of scheduler load that isn't needed, even if they are "idle".

Also, MMCS, I don't believe, is used by games. Then again, I've been out of the industry for over 20 years, maybe they use it now. It's used by actual "Real-Time" tasks, like precision audio playback. Ok, maybe it is used by games. But I would be surprised.

I wouldn't be that surprised, that by tweaking those values, you actually degrade the performance of non MMCS-aware apps.

Also, the default NT scheduler, since like the beginning that I am aware of, has a maximum unscheduled task/thread timeout, that when it is reached, those low-priority tasks gets FORCIBLY scheduled on the CPU, EVEN WHEN A HIGHER-PRIORITY thread is pending scheduling.

This is why, I believe, running modern multi-threaded games on a G3258 is "stuttery"... because there aren't enough cores/hyperthreads for allowing background task threads to execute in a timely matter, so NT scheduler is FORCIBLY pausing the main game loop task, every 1-2 seconds, to run those background threads. Something that isn't observed, if there are HyperThreads available to be loaded.
 

shortylickens

No Lifer
Jul 15, 2003
79,047
11,965
126
Is this really y'all's advice for this guy? I've never seen such terrible advice in my life. You do realize this is a TECH forum right, so when a person asks a tech question, one would guess (ya think?) that they expect a tech answer; not an answer like "No, don't touch that" or "stick with default" or "windows knows best", lol, wth. Do any of you really have any degree or experience or technology? please shock me.

Okay friend. For the record everyone who responded to you is a PROVEN noob, and this is the evidence:


Go down to "More Gaming Tweaks"

Thank me later. And if anyone ever tells you Microsoft or Windows knows something, or even Apple for that matter, you are not in a tech forum; they are not a tech. God bless.
Its six years old, -------------.
And its the PC gaming subforum, not the tech advice forum, where he should have asked.
 

DigDog

Lifer
Jun 3, 2011
11,925
1,209
126
Hi, hey. Quake guy here.

For years i have been maniacal about my windows settings to squeeze every last millisecond of response from my system. From setting priorities, to manually nuking whole chunks of my services / registry, using only medieval-era video drivers, you know, THE GOOD STUFF.

And what i can say is, it doesn't work like that.

Back when you had DDR1 and single core PCs, then yes, you could in fact lower system latency by making sure that nothing got actioned before *whatever game you were running*. Windows does not work like that anymore. EVERYTHING windows does has latency, now. This is done to increase stability, but also to account for better efficiency and higher workloads.

I guess if you coded your own Unix OS then yeah, you could getter a more responsive system. But if you want to actually use your computer, then you have to deal with the (arguably superior) way that Windows distributes the various processes it need to function over its hardware.

Maybe - since you want to bring the N-word in this - you could stop being one and think that 10ms latency is what divides you from the likes of Rapha.

sincerely
this guy
<-
 

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