Would disabling CPU threads give better performance?

[DanWhite]

So this is a laptop with the Ryzen 5 3450u which is el weako CPU (only 15 watt, of which are shared between all the cores) so, would disabling half of the cores be better? so the remaining ones have more power to use and can run at higher frequencies? also maybe have more power available for the Vega 8 IGPU to use? I don't know, this is a 4C 4T CPU, if you have any idea about what would be better would appreciate if you guys can let me know, thank you in advance.

 

Ideally I don't really care about multi-tasking, that would be for what the extra cores are meant for I think, I'm using WIndows 11

[igormp]

It depends on your workloads. If you are mostly using single threaded applications, then unused cores will barely use any power, leaving most of the power budget to the working core to use.

 

However, if you deal with any multithreaded scenario, even if you leave more power to only 2 cores with other 2 disabled, it's still going to be slower than having all 4 cores running at reduced clock speeds.

 

tldr; not worth it, leave them enabled.

 

5 minutes ago, DanWhite said:

Ideally I don't really care about multi-tasking, that would be for what the extra cores are meant for I think, I'm using WIndows 11

The system itself has background stuff running, and most of the applications on your daily basis make use of multiple threads, so they do benefit from extra cores. Having a single core switching between what to work on every time would be a bad experience.

[Bad5ector]

If it were me, I wouldn't bother, unless my daily computer use relied on the fastest single thread CPU.

[Eigenvektor]

12 minutes ago, DanWhite said:

Ideally I don't really care about multi-tasking, that would be for what the extra cores are meant for I think, I'm using WIndows 11

You may think you don't, but you do. If you have more than one tab open in your browser, e.g. running YouTube in one and this forum in another, you're already multi-tasking. That virus scanner running in the background? Multi-tasking. If you disable cores this will barely increase the power/thermal budget for the others and you'll most likely have a worse experience all around.

[DanWhite]

1 hour ago, igormp said:

It depends on your workloads. If you are mostly using single threaded applications, then unused cores will barely use any power, leaving most of the power budget to the working core to use.

 

However, if you deal with any multithreaded scenario, even if you leave more power to only 2 cores with other 2 disabled, it's still going to be slower than having all 4 cores running at reduced clock speeds.

 

tldr; not worth it, leave them enabled.

 

The system itself has background stuff running, and most of the applications on your daily basis make use of multiple threads, so they do benefit from extra cores. Having a single core switching between what to work on every time would be a bad experience.

But there are 4 cores and 4 threads, games and stuff use 4 cores right? so why would I need the rest, also I'm either gaming or using the browser not both. My idea was keeping 4 cores and disabling the other 4 threads or whatever

[DanWhite]

55 minutes ago, Eigenvektor said:

You may think you don't, but you do. If you have more than one tab open in your browser, e.g. running YouTube in one and this forum in another, you're already multi-tasking. That virus scanner running in the background? Multi-tasking. If you disable cores this will barely increase the power/thermal budget for the others and you'll most likely have a worse experience all around.

But do I need 8 cores for that for example tho? and for gaming, wouldn't it be better to have just 4 cores and disabling the other 4 threads or whatever?

[DanWhite]

1 hour ago, Bad5ector said:

If it were me, I wouldn't bother, unless my daily computer use relied on the fastest single thread CPU.

Does gaming not rely on that? is it really preferable to have 8 cores(4C, 4Threads) for playing games?

[Bad5ector]

28 minutes ago, DanWhite said:

Does gaming not rely on that?

Depends on the game, but I can assure you that you won't be blown away by the performance increase if the game you were playing was a heavily single threaded. Again, like others have stated, not worth the effort. But feel free to try and report back. 

[DanWhite]

30 minutes ago, Bad5ector said:

Depends on the game, but I can assure you that you won't be blown away by the performance increase if the game you were playing was a heavily single threaded. Again, like others have stated, not worth the effort. But feel free to try and report back. 

Not single threaded, not talking about that, just it not really making use of the extra 4 cores, as what I could read after searching it up it says not many games do make use of 8 threads really

[Bad5ector]

Sigh... fine disable SMT and tell us all about your amazing gains then.

[DanWhite]

1 minute ago, Bad5ector said:

Sigh... fine disable SMT and tell us all about your amazing gains then.

Sigh *refuses to elaborate* what's that attitude, you said something and I told you that that was not what I was talking about and then I just asked a question, if you wanna respond do it like a normal person don't be acting like that

[igormp]

10 minutes ago, DanWhite said:

Not single threaded, not talking about that, just it not really making use of the extra 4 cores, as what I could read after searching it up it says not many games do make use of 8 threads really

Those are not extra "4 cores", each physical core has 2 threads within it thought SMT (simultaneous multi threading), which allows the system to make better use of the execution units inside the CPU. Disabling those usually leads to worse utilization, so your CPU would spend more time idle.

 

With AMD you usually get gains of past 40% having it enable, there's NO benefit whatsoever by disabling those, and it wouldn't change anything in your power budget (since you still only have 4 physical cores, SMT enabled or not), and disabled 2 actual physical cores is another bad idea on its own.

[DanWhite]

7 minutes ago, igormp said:

Those are not extra "4 cores", each physical core has 2 threads within it thought SMT (simultaneous multi threading), which allows the system to make better use of the execution units inside the CPU. Disabling those usually leads to worse utilization, so your CPU would spend more time idle.

 

With AMD you usually get gains of past 40% having it enable, there's NO benefit whatsoever by disabling those, and it wouldn't change anything in your power budget (since you still only have 4 physical cores, SMT enabled or not), and disabled 2 actual physical cores is another bad idea on its own.

How do I know which are the physical cores and which are the threads?

[Bad5ector]

12 minutes ago, DanWhite said:

Sigh *refuses to elaborate* what's that attitude, you said something and I told you that that was not what I was talking about and then I just asked a question, if you wanna respond do it like a normal person don't be acting like that

Check out the posts from everyone on this thread... do you sense a theme????? I sighed because I was getting tired with telling you that disabling SMT was a bad idea. It didn't seem you wanted to listen to mine or anyone else's advice.

 

2 hours ago, igormp said:

tldr; not worth it, leave them enabled.

 

2 hours ago, Bad5ector said:

If it were me, I wouldn't bother, unless my daily computer use relied on the fastest single thread CPU

 

9 minutes ago, igormp said:

With AMD you usually get gains of past 40% having it enable, there's NO benefit whatsoever by disabling those

 

1 hour ago, Bad5ector said:

Depends on the game, but I can assure you that you won't be blown away by the performance increase if the game you were playing was a heavily single threaded. Again, like others have stated, not worth the effort. But feel free to try and report back. 

 

[igormp]

13 minutes ago, DanWhite said:

How do I know which are the physical cores and which are the threads?

You don't. All cores are logical with SMT enabled, and if you disabled it then all of them become physical.