12 core cpu, limiting affinity to reduce stress

[1984]

Just wondering if this is an okay thing to do because most games do not use all 12 cores but sometimes they still work to their full potential which means unnecessary temps and workloads.
Is this an okay thing to do? Limit the amount of cpus needed as per recommended settings?

Edit: basically is it okay to limit affinity just to expand CPU lifespan because less CPU use -> lower temps -> longer life

[Cathulhu]

That doesn't make sense, if a game does not use all 12 cores, then the CPU will not use all 12 cores for the game. Unused cores will stay idle.

[r.linder]

If this 12-core CPU has more than one chiplet (3900X), then limiting affinity to cores that are part of only one chiplet improves performance if the chiplet communication latency poses an issue.

Example game: 7 Days To Die

Stock: Game can stutter a lot, low FPS
Affinity limited to 4 cores on CCD 1: No stuttering, proper FPS

[r.linder]

Originally posted by ZERO KAY PER CENT:

Originally posted by Escorve:

If this 12-core CPU has more than one chiplet (3900X), then limiting affinity to cores that are part of only one chiplet improves performance if the chiplet communication latency poses an issue.

Example game: 7 Days To Die

Stock: Game can stutter a lot, low FPS
Affinity limited to 4 cores on CCD 1: No stuttering, proper FPS

I got 3900x. games do not stutter. But I limited affinity on Destiny and my temps reduced from 70 all cores working, to 55 just 4 cores working. Dual thread

Since it's using less cores and task scheduler isn't bouncing what cores are being used around.

Stuttering/low FPS depends on the game and how it handles Ryzen. For games that it does seem to perform like a Core 2 Duo, limiting affinity to CCD1 cores or using Ryzen Master's Game Mode preset (disabling CCD2) will fix performance.

[r.linder]

Originally posted by ZERO KAY PER CENT:

Originally posted by Escorve:

Since it's using less cores and task scheduler isn't bouncing what cores are being used around.

Stuttering/low FPS depends on the game and how it handles Ryzen. For games that it does seem to perform like a Core 2 Duo, limiting affinity to CCD1 cores or using Ryzen Master's Game Mode preset (disabling CCD2) will fix performance.

Okay, but can we get back to the topic on hand. I google how to limit used CPU cores and it came up with limiting affinity.

The only reason I need to limit affinity is because Ryzen is a bit of an overkill for videogames and many games that do not need the full force, still use them all and it runs all the same without hiccups with limited cores.
So question is, is it okay to limit affinity just to expand CPU lifespan because less CPU use -> lower temps -> longer life

It's fine, but you don't limit it to too few cores, because the games can become unstable and crash. I would stick to 4(~6 cores with newer titles).

Also it has nothing to do with the core count with potential performance issues, Ryzen 9's multiple chiplets has a latency between them that occurs when two or more cores from both chiplets are being used for the application. Depending on the application, the latency can reduce performance in that instance.

[_I_]

setting affinnity could help, keeping the program to specific cores
each bank/module of cores has seperate cache, saving time/cycles swapping cache between banks

if the cpu has 12 cores (4 bank)
but if its a 6 core (non fx) with smt/ht it wont make a difference

[Snow]

70 degrees barely tickle CPU, it's not going to live less or something. But you absolutely do want to limit affinity to get a bit better performance, Escorve and _I_ did an awesome job explaining it. Process Lasso can save affinities and apply them once apps launch so you won't have to do it all manually.

[_I_]

you can also use a shartcut
start 'program path/name' /affinity 0x###
to set cores on launch
https://www.tenforums.com/performance-maintenance/47607-affinity-command-cmd.html

easiest to use a calc to convert core values from binary to decimal/hex

0= off, 1 = on
starting with highest core (11,10,9,8,7,6,5,4,3,2,1,0)
0 0 0 0 1 0 1 0 1 0 1 0 (cores 1,3,5,7 = 170 d = 0xAA h)
1 0 1 0 1 0 1 0 0 0 0 0 (cores 5,7,9,11 = 2720 d = 0xAA0 h)

[_I_]

easier than it sounds
create a new shortcut for the program
edit the target line to
start "xxxxx" /affinity 0xAA
when that shortcut is launched, it will start the program with affinity set to those cores

[Snow]

Originally posted by ZERO KAY PER CENT:

Originally posted by _I_:

easier than it sounds
create a new shortcut for the program
edit the target line to
start "xxxxx" /affinity 0xAA
when that shortcut is launched, it will start the program with affinity set to those cores

ok, but wasn't I just told that it is better not to set affinities anyway?

We all were saying quite the opposite. You do want to set affinities to get better performance.

[Clint E]

Interesting topic , I haven't had these experiences yet on my 3900, will download some of the mentioned games to see. Don't have anything to add to this but found it interesting/

[Autumn_]

Originally posted by ZERO KAY PER CENT:

Originally posted by Snow:

We all were saying quite the opposite. You do want to set affinities to get better performance.

oh right. performance itself is not an issue. I get more fps than my screen can ever show me lol.

Refresh rate =/= FPS.
You can see hundreds of FPS on a 60hz monitor, though they'll be partial frames.
The monitor however would only update the picture 60 times a second.

But, to answer your main question;

Originally posted by ZERO KAY PER CENT:

Edit: basically is it okay to limit affinity just to expand CPU lifespan because less CPU use -> lower temps -> longer life

You wouldn't impact the CPU life span at all.
The CPU still warms up and cools down, thus is getting damage (not anything to worry about.)
By changing what cores it happens on won't do anything.
Though, it is good for lowering temps because you're not spreading the load over more cores, so you're pulling less power, which produces less heat. So the only thing you're really doing is making your system quieter, and improving performance (if it's on the same CCD, and boosts higher than all the cores, which it will.)

[vadim]

Originally posted by ZERO KAY PER CENT:

Edit: basically is it okay to limit affinity just to expand CPU lifespan because less CPU use -> lower temps -> longer life

CPU lifespan doesn't depend on temperature (it is pretty obvious, but I should add for local trolls: if temperature stays within designed range).

[_I_]

newer cups will thorttle when hot, even without a cooler, well before any damage is done

[r.linder]

Originally posted by vadim:

Originally posted by ZERO KAY PER CENT:

Edit: basically is it okay to limit affinity just to expand CPU lifespan because less CPU use -> lower temps -> longer life

CPU lifespan doesn't depend on temperature (it is pretty obvious, but I should add for local trolls: if temperature stays within designed range).

But unless the cooler is too inefficient even to handle a throttled chip, it'll never be out of the safe range for long. So temperature has almost nothing to do with it.

You can make a case for overclocking, but that's completely out of manufacturer spec and more of the fault of the user for having a bad overclock.

[hawkeye]

Stress and lifespan? I've never heard of a cpu needing to be replaced in any system. Even 10 year old overloaded servers that had been running max load cpu usage 24/7. (Faulty boards in board-mounted cpus excepted.)

I would limit a game to one chiplet anyway. First gen intels (ix-xxx cpus) used a similar design to the amd 3900x. That created memory latency in a similar way to how infinity fabric does. So running on one chiplet should be more efficient and reduce temps. Non-cached data i/o would still need to run via the infinity fabric which would slow things down but not as bad as having multiple cpu caches.