Question Setting affinity of cores ?

[Deleted member 2942093]

When playing a game and I disable CPU 0 and CPU 1 will it use CPU 2, 3 , 4, 5 and so on depending on the game

 

[USAFRet]

When playing a game and I disable CPU 0 and CPU 1 will it use CPU 2, 3 , 4, 5 and so on depending on the game

Why would you disable parts of your CPU?

 

[TerryLaze]

When playing a game and I disable CPU 0 and CPU 1 will it use CPU 2, 3 , 4, 5 and so on depending on the game

Well if you disable them they won't exist (for the OS) so what else are games going to use than the rest of the cores?!
Also you don't need to disable cores, you can use process lasso/hacker or just plain old task manager (go to detail tab and right click on an app) to force an app to only use the cores you want it to use.

 

[hotaru.hino]

To answer the question, yes, unticking the boxes for the CPUs will cause Windows to schedule the application somewhere else.

But there's no real need to do this.

 

[DSzymborski]

The situations you'd want to do this are quite limited. I did have one of those, with Madden 08 PC. A lot of people played that for a long time since there wasn't another Madden release for a PC until more than a decade later. But it gradually got more and more out of date with modern CPUs and by the time I had a Coffee Lake Refresh, it was sufficiently archaic that it would stutter, skip, and have random crashes, and one of the common fixes for it was to set it to run on only one core every time you started the software.

These are rare things though.

 

[drea.drechsler]

When playing a game and I disable CPU 0 and CPU 1 will it use CPU 2, 3 , 4, 5 and so on depending on the game

How are you disabling the two logical CPU's? If in BIOS or in MSConfig then you're disabling them for the entire computer and not just the game. There's no real benefit I can see to cutting out 1/3 of the computing power of your system.

The SMART way to disable them for the game only is in Task Manager, the Details screen, Affinity. That at least leaves those cores available for the system to use. But which process to set affinity for? I believe the most obvious one is usually just a game launcher so it won't have much effect on anything in-game. But yes, when you find the right process it will use ONLY the CPU's (logical CPU's actually) you tell it.

 

[Deleted member 2942093]

How are you disabling the two logical CPU's? If in BIOS or in MSConfig then you're disabling them for the entire computer and not just the game. There's no real benefit I can see to cutting out 1/3 of the computing power of your system.

The SMART way to disable them for the game only is in Task Manager, the Details screen, Affinity. That at least leaves those cores available for the system to use. But which process to set affinity for? I believe the most obvious one is usually just a game launcher so it won't have much effect on anything in-game. But yes, when you find the right process it will use ONLY the CPU's (logical CPU's actually) you tell it.

CS GO uses only 4 cores. I've been told core 0 runs background apps and disable cpu 1 for hyper threading.

CS is processor demanding

 

[Karadjgne]

CSGO uses 2 threads, which at most is 2 cores, but can be 1 core with HT depending on the cpu and other processes being run. That's a hard code game limitation so has no affect on the cpu as is. It'll run 2 threads whether on an old Pentium 4 or a 64core Epyc cpu.

There's nothing saying that a cpu must try and use every available core, or only specific threads. The cpu scheduler will decide which threads get used at any particular time.

The reason it can show upto 100% usage on those 2 threads is because that's the game code limitation. There's no rollover, where another thread can be used as supplemental help. So when you are pushing 500fps from a 13900k, all 500fps are coming from just 2 threads, so will show a high usage %. The remaining 30 threads will be doing exactly nothing but running Windows and any other background tasks.

CSGO could run on a potato, it's as low demanding on a modern cpu as is possible and still be called a game.

 

[Deleted member 2942093]

CSGO uses 2 threads, which at most is 2 cores, but can be 1 core with HT depending on the cpu and other processes being run. That's a hard code game limitation so has no affect on the cpu as is. It'll run 2 threads whether on an old Pentium 4 or a 64core Epyc cpu.

There's nothing saying that a cpu must try and use every available core, or only specific threads. The cpu scheduler will decide which threads get used at any particular time.

The reason it can show upto 100% usage on those 2 threads is because that's the game code limitation. There's no rollover, where another thread can be used as supplemental help. So when you are pushing 500fps from a 13900k, all 500fps are coming from just 2 threads, so will show a high usage %. The remaining 30 threads will be doing exactly nothing but running Windows and any other background tasks.

CSGO could run on a potato, it's as low demanding on a modern cpu as is possible and still be called a game.

So disabling first two cores with affinity is not going to make a difference? What are your thoughts on high priority for CSGO?

 

[hotaru.hino]

So disabling first two cores with affinity is not going to make a difference? What are your thoughts on high priority for CSGO?

If you're using a CPU that has preferred cores (which are the ones that can turbo boost the highest) and it just so happens those preferred cores happen to be the ones you've disabled, then it might. Otherwise no.

Setting a high priority is also not going to make a difference.

 

[Deleted member 2942093]

If you're using a CPU that has preferred cores (which are the ones that can turbo boost the highest) and it just so happens those preferred cores happen to be the ones you've disabled, then it might. Otherwise no.

Setting a high priority is also not going to make a difference.

How can I tell which processors get the best Turbo boost speed? And if I Set an overclock on all the processors and disabling c states Does that mean all of the processor course will run the same?

 

[hotaru.hino]

How can I tell which processors get the best Turbo boost speed?

If you're using a Ryzen processor, use HWiNFO. The lower the "perf" number, the higher the preference:

Intel CPUs since 12th gen may have it, but I'm not sure how to figure it out other than run a single core load and see where it ends up most of the time.

And if I Set an overclock on all the processors and disabling c states Does that mean all of the processor course will run the same?

That depends on the behavior of the processor. I know for AMD processors, if you set a manual clock frequency, it'll force the entire processor to run at that speed.

 

[Karadjgne]

And if I Set an overclock on all the processors and disabling c states Does that mean all of the processor course will run the same?

Ryzen boosts to its max ability according to voltages, temps and loads, it's not an intel. The OC as was common years ago is pointless unless you have a golden cpu that'll run very low voltages and very low temps yet still get higher than boost speeds. Cpus today have double or more the amount of cores as cpus a few years ago, so OC set values on All those cores takes a much larger amount of power and creates more heat than is necessary, and generally doesn't meet the turbo boosts of 1-3 cores and has a rough time equalling 4-6 cores speeds.

OC is effectively dead. Both Intel and amd have boosted performance stock to basically equal what OC was years ago. An intel i7-3770K would stock turbo to 3.9GHz, but OC with good cooling could reach 5.0GHz, so was worth the effort. A 13900k can boost stock to 5.3GHz on a single core. Good luck trying to get all 8 Performance cores to that level on anything less than liquid nitrogen.

Best bet is to undervolt the cpu slightly, lower the overall temps, and call it a day.

 

[TerryLaze]

A 13900k can boost stock to 5.3GHz on a single core. Good luck trying to get all 8 Performance cores to that level on anything less than liquid nitrogen.

5.5Ghz on all main cores is pretty much the normal on air or good liquid cooler, single core is 5.8 the ks is 6Ghz...where do you get your info from?!
https://www.techpowerup.com/review/intel-core-i9-13900k/24.html

 

[Karadjgne]

Same places you do, only there are occasions where my phone does this autocorrect thing, and changes what I've typed to what it thinks it should be, and I was tired and didn't see that change from 5.8GHz to 5.3GHz 🙄