Single core overclocking for games

[Samuel Vertex]

Hello,

 

Just asking out of curiosity, I understand that most old games only use a single thread. Correct me if I'm completely wrong about this whole thing, but clock speed of the CPU is proportional to the performance of the game (that is if there's currently a CPU bottleneck).

 

I also understand that individual cores can have different clocks from the rest of the cores. So is there a way of super clocking one core and assigning that core for the game?

 

One method i thought of if single core overclocking is not possible, or viable, is using an unlocked 8 core cpu as an example, in order to achieve high clock speeds I could deactivate 6 cores and really crank up the clock speeds, higher than the speeds that I would get if all cores are active.

 

Therefore I would get better performance for a single threaded game, right?

 

How viable is this option?

 

[Chris Pratt]

No, you're incorrect on your base premise. Single core performance is important because games often use a world thread, but that doesn't mean nothing else at all is going on. Multicore performance still matters, and increasingly so, as modern games take more advantage of the higher number of cores available to them. You can't have one god thread and ditch the rest.

[YoungBlade]

This might make sense is if you have a couple of dud cores that won't overclock well at all, but the remaining cores do. You could lose the dead weight by deactivating them, allowing the remaining cores to achieve their full potential.

 

Another reason could be for thermal headroom. If you can't keep 8 cores cool at your desired overclock, dropping to 6 or 4 could fix the problem.

 

I wouldn't recommend going as low as 2 cores, even for very old games, unless you have nothing else going on in your system and can't get a stable overclock with more cores. 4 cores with SMT/HT is really the minimum necessary for a reasonable gaming experience.

[mariushm]

While the game itself may use one or two threads, the video card driver also does a lot of work in its own thread or multiple threads. (so not just one core will be used).

 

On modern processors like Ryzen, they're fairly well designed to automatically boost cores that are used more, so it's not like an old game will really benefit from you manually overclocking particular cores.

You could set affinity to make a game use only specific cores and overclock those cores to the maximum if you really want to experiment, but my guess  is you'll be disappointed by the results. 

[Hairless Monkey Boy]

46 minutes ago, Chris Pratt said:

No, you're incorrect on your base premise. Single core performance is important because games often use a world thread, but that doesn't mean nothing else at all is going on. Multicore performance still matters, and increasingly so, as modern games take more advantage of the higher number of cores available to them. You can't have one god thread and ditch the rest.

I disagree with this. OP specifically is talking about "older games". While it is true that modern games take better advantage of multi-threaded CPUs, older games didn't always, and often didn't. If OP gave us a specific game, we could give a better answer, but in theory the logic is sound.

 

You can, in fact, OC your CPU quite a bit further by disabling cores. I know because I've done it with my 9900K just for fun. If a game is heavily single thread dependent, then it stands to reason that you can gain performance by disabling unneeded CPU cores and boosting the OC of the remaining cores.

 

I would hypothesize that dropping to 2 active cores (4 threads) is not "optimal" for a single-thread game since the game engine would be competing for CPU cycles with the OS and other background tasks, but perhaps 3 or 4 active cores would OC further and perform better than the full 6 or 8 active cores that you have by default while providing enough extra CPU cycles to sustain the OS and background tasks separate from the game.

 

It would certainly be an interesting theory to test at the very least.

[Light-Yagami]

@Samuel Vertex

New CPUs support per core overclocking or at least per CCX overclocking (on AMD). Check SkatterBencher on Youtube, he does extensive overclocking guides for a number of CPUs.

 

But the gist of the matter is - if you have an 8 core CPU, you wanna have 2-4 of those cores clocked as high as you possibly can for best gaming performance, but not disable the rest. Games still use 8 core quite efficiently.

 

I think that with AMD, you can even set clock multiplier based on load. So, if you exceed 50A for example, the clocks will drop - but if you stay below that, it'll boost much higher. Good for gaming, safe for heavy workloads. 

 

It's quite a rabbit hole. But in general - yes, having a few cores clocked much higher will benefit your gaming performance.

[Samuel Vertex]

Ok, very interesting. Thanks everyone.