One of the novelties of the Alder Lake-S architecture is the implementation of highly energy efficient CPU cores for background tasks or lower computational load. Well, Intel allows you to disable these E-Cores to reduce consumption and temperature, but apparently this has no performance effect in games. How is it possible?
One of the problems that PC game development studios are going to face with the launch of the Intel Core 12 is the allocation of processes to the different 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 that, 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 under the premise of fully symmetric processors.
Obviously, developers will eventually get the hang of E-Cores when assigning tasks to them, but current software is not designed that way and performance can suffer in the process. That is why Intel gives the ability to deactivate the E-Cores, but not in order to facilitate the allocation of processes in execution threads, but rather in order to allocate energy for overclocking.
Intel allows you to disable the E-Cores on your new CPU
One of the essential elements of the Power Delivery Network in every processor is the ability to disconnect parts of it to save power when not in use or to give more power to others. As well, in the Intel Core 12 the E-Cores can be deactivated 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, deactivating the E-Cores causes the 20% consumption reduction for the entire CPU and one 5º drop in temperature of the same. As for it does not affect performance in games, it is something that we are skeptical, especially due to the fact that not only the game runs on the PC but also a huge number of background processes that benefit from the use of E- Cores.
What background applications are we talking about? Well, we can talk about Discord, OBS, hardware monitoring tools, and so on. All of them benefit from being assigned to other nuclei, by the simple logic of the division of labor.
PC games and threads
One of the peculiarities of the E-Cores is that they add a 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 symmetric processor with equal threads. If we are lucky and the processes do not require much power then there will be no performance cut, but if not then we will.
PC video games for their optimization adapt to the amount of hardware threads available to distribute their tasks. The problem is that many of these threads are synchronous between cores, since they assume that all the CPU cores running them are running at the same speed or at least a good part of them. When you need to synchronize a process that works in parallel then it will be as fast as the part that is slower.
Hence the paradox that deactivating the E-Cores gains performance in some games or is not affected, although Intel has not thought of it for that, but for those who want more clock speed in the P-Cores of their Intel Core 12.