One of the new features of the Alder Lake-S architecture is the implementation of energy efficient processor cores for background tasks or lower compute load. Well, Intel allows these E-Cores to be disabled to reduce power and temperature, but apparently that has no effect on performance in games. How is it possible?
One of the issues that PC video game development studios are going to face with the launch of the Intel Core 12 is the allocation of processes to the various cores of said CPU. Let’s not forget that the configuration of the new Intel CPU is asymmetric and combines two different types of cores which, although they share the same ISA and are binary compatible, do not have the same performance. Which is a problem for a platform like the PC where games have always been developed on the principle of fully symmetrical processors.
Obviously, developers will eventually master E-Cores when they assign tasks to them, but current software is not designed that way and performance can suffer. This is why Intel gives the possibility of deactivating the E-Cores, but not to facilitate the allocation of the processes in the execution threads, but rather in order to allocate energy for overclocking.
Intel allows you to disable E-Cores on your new CPU
One of the essential elements of the power distribution network in each processor is the ability to disconnect parts of it to save power when not in use or to give more power to others. Also, in Intel Core 12 E-Cores can be disabled so that the energy goes to the P-Cores or simply that the consumption of these alone is lower.
The result? As you can see in the image above, disabling E-Cores causes the 20% reduction in consumption for the entire CPU and an 5º temperature drop of the same. As for the fact that it does not affect performance in games, this is something that we are skeptical, especially given the fact that not only does the game run on the PC but also a large number of processors. ‘background that benefit from the use of E-Cores.
What background apps are we talking about? Well, we can talk about Discord, OBS, hardware monitoring tools, etc. All benefit from being assigned to other nuclei, by the simple logic of the division of labor.
PC games and discussion threads
One of the great things about E-Cores is that they add a certain number of additional threads to the CPU, so for video games if they see an Intel Core 12 with a specific number of threads, they will try it as a symmetrical processor with an equal threads. If we’re lucky, and the processes don’t require a lot of power, there won’t be any drop in performance, but if not, we will.
PC video games for their optimization adapt to the amount of hardware threads available to distribute their tasks. The problem is, a lot of these threads are synchronous between cores, because they assume that all of the processor cores that are running them are running at the same speed, or at least a good chunk of them. When you need to synchronize a process that is running in parallel, it will be as fast as the slowest part.
Hence the paradox that disabling E-Cores can improve performance in some games or is not affected, although Intel has not thought of it for that, but for those who want more speed of clock in the P-Cores of their Intel Core 12.
