Question about Intel's new CPUs (P cores and E cores)

[PackYourBaggins]

I just got done watching Linus's video review and benchmarks of the 12900K and 12600K and I still need a little clarification on the P cores and E cores. My question is, do E cores do nothing for gaming? Towards the end of the video when talking about gaming specifically, Linus referred to the 12600K as a "6 core processor" because it has 6 P cores. But it also has 4 E cores for a total of 10 cores, and it is listed on websites as a 10 core CPU. Do games only utilize the P cores? I might've missed something in the video where this is more clear, but it wasn't obvious to me.

[dizmo]

Depends on the game. Some, you'll see a performance increase with them on, some you won't.

[PackYourBaggins]

2 minutes ago, dizmo said:

Depends on the game. Some, you'll see a performance increase with them on, some you won't.

Wait, can you turn cores on and off?

[dizmo]

4 minutes ago, PackYourBaggins said:

Wait, can you turn cores on and off?

Yes.

[PackYourBaggins]

3 minutes ago, dizmo said:

Yes.

What would be the purpose of turning them off?

[adarw]

4 minutes ago, PackYourBaggins said:

What would be the purpose of turning them off?

overclocking pretty much.

[PackYourBaggins]

2 minutes ago, adarw said:

overclocking pretty much.

So only the P cores can be OC'd?

[adarw]

Just now, PackYourBaggins said:

So only the P cores can be OC'd?

no to my limited understanding (i could be totoally wrong) but people turn off the e cores to overclock the p cores even more since p cores are the ones that do most of the heavy lifting.

[unclewebb]

@PackYourBaggins Here is a good review that will show you what games and software benefit from the E cores.

 

https://www.techpowerup.com/review/intel-core-i9-12900k-e-cores-only-performance/

 

This is new technology. It always takes programmers a while to fully take advantage of any new hardware.

[PackYourBaggins]

21 minutes ago, unclewebb said:

@PackYourBaggins Here is a good review that will show you what games and software benefit from the E cores.

 

https://www.techpowerup.com/review/intel-core-i9-12900k-e-cores-only-performance/

 

This is new technology. It always takes programmers a while to fully take advantage of any new hardware.

Oh, this is really helpful. So from what I understand now, most games that are out right now probably won't benefit from the E cores, and in some cases, the E cores can even hinder gaming performance. In which case, if I'm eyeing an i7 12700K 12 core CPU for example, it's really an 8 core CPU when gaming and 12 cores for most other applications. 

[Slizzo]

If the game is aware and able to use more than 8 cores, having the E cores would help with an application that spills over the 8 available P cores.

 

Other than that, should not hurt things. The hardware scheduler on the CPU should do most of the heavy lifting. But there have been cases where E cores do cause issues. This will get better over time of course with Windows updates and just hybrid CPUs being more commonplace.

[jaslion]

On 11/22/2021 at 8:09 AM, PackYourBaggins said:

Oh, this is really helpful. So from what I understand now, most games that are out right now probably won't benefit from the E cores, and in some cases, the E cores can even hinder gaming performance. In which case, if I'm eyeing an i7 12700K 12 core CPU for example, it's really an 8 core CPU when gaming and 12 cores for most other applications. 

You should more see it as a it is a 8core/16thread cpu for all intensive tasks and has 4 cores for windows and background tasks available.

 

For tasks that use 100% of the cpu like rendering the e cores are basically just slower cores and the system doesn't really care about what is a p or e core then.

 

So basically you buy a 11900k + a i5 7400 strapped onto it for the light tasks :p.

 

It's why in windows 10 performance is all over the place too because windows just doesn't know what to do with the p and e cores and uses whatever it wants. Since sometimes it's gonna use some e cores for gaming and a couple p cores for the lighter tasks of the game.

[YoungBlade]

On 11/22/2021 at 2:09 AM, PackYourBaggins said:

Oh, this is really helpful. So from what I understand now, most games that are out right now probably won't benefit from the E cores, and in some cases, the E cores can even hinder gaming performance. In which case, if I'm eyeing an i7 12700K 12 core CPU for example, it's really an 8 core CPU when gaming and 12 cores for most other applications. 

It's 8 cores for applications that use 8 or fewer threads, up to 12 cores for ones that use up to 16 threads, and 12 cores for ones that use 20 or more threads. The thread scheduler is actually designed to prioritize E cores over putting a second thread on a P core in theory, although this clearly is not always the case.

 

Honestly, don't think about cores for applications like games. The core count itself almost never matters for a game. It's the overall CPU performance and single-core performance that matters for games. Only a fool would buy an old 12 core Xeon from 2014 over something like a 5600X or 11600K for gaming. It has double the cores, but less overall performance and way lower single-core performance.

[Falkentyne]

If your game or application doesn't make use of more than 16 threads, unless you're doing multitasking (like streaming), you'll get more performance by just buying a 12900k, disabling the E cores and then yeeting the cache ratio.  Average chips should have no difficulty doing x52 P cores and x48-x49 cache ratio., although it may require anywhere between 1.20v to 1.30v load voltage to be stable, depending on your chip's silicon quality and what you're trying to run on it (Lower vmin required for stability=better chip).

Average chips may be able to game at x53 on the P cores, but anything that puts a momentary load on all the cores at once (minecraft launcher loading, etc) may require more than 1.32v load voltage to not BSOD on you during that (and may get up to 100C just launching minecraft).  Good silicon quality chips should be able to do this on less than 1.30v load and the best chips on less than 1.25v load (those are golden chips), with a 360mm AIO as your target cooler.

[PackYourBaggins]

On 11/25/2021 at 12:56 AM, Falkentyne said:

If your game or application doesn't make use of more than 16 threads, unless you're doing multitasking (like streaming), you'll get more performance by just buying a 12900k, disabling the E cores and then yeeting the cache ratio.  Average chips should have no difficulty doing x52 P cores and x48-x49 cache ratio., although it may require anywhere between 1.20v to 1.30v load voltage to be stable, depending on your chip's silicon quality and what you're trying to run on it (Lower vmin required for stability=better chip).

Average chips may be able to game at x53 on the P cores, but anything that puts a momentary load on all the cores at once (minecraft launcher loading, etc) may require more than 1.32v load voltage to not BSOD on you during that (and may get up to 100C just launching minecraft).  Good silicon quality chips should be able to do this on less than 1.30v load and the best chips on less than 1.25v load (those are golden chips), with a 360mm AIO as your target cooler.

If I'm being honest with you, you lost me a little bit talking about the cache ratio. I didn't even know you could mess with the cache of a CPU after all these years.

 

So moral of the story is that turning off E cores for gaming isn't necessary?