A new Intel developer guide reveals some key details about Alder Lake and how game developers can best optimize titles for it. The hybrid architecture on Alder Lake chips requires developers to tweak their games for best performance — but the developer guide also revealed that not all Alder Lake chips will have the hybrid design.
That is the most striking news from the guide. It reads: “Mobile SKUs will contain up to 6 P-cores and 8 E-cores. All mobile SKUs will contain E-cores. Desktop SKUs will contain up to 8 P-cores and up to 8 E-cores. Dedicated desktop SKUs will contain only P-cores.”
If you’re unfamiliar, Alder Lake uses a hybrid architecture that combines high-performance (P) cores and efficient (E) cores, but this is the first time Intel has said some models will only include P-cores. It confirms a rumor from earlier this week that showed the Core i5-12400 with six P-cores, for a total of 12 threads.
However, we don’t suspect that Intel makes non-hybrid models for all of its chips. The guide also points to up to eight P-cores and eight E-cores on desktop chips, which is what the Core i9-12900K is said to be coming with. We’ll probably see a few select models, like the Core i5-12400, which are built to excel in limited-thread applications like gaming at a reasonable price.
While games don’t benefit much from having many cores, Intel’s developer guide does offer some important tips. Unlike a normal desktop CPU, which can schedule tasks on any available core, Alder Lake requires careful planning from developers to move the most important tasks to the highest performing cores.
This is where Intel Thread Director comes in. It gives Windows 11 insight into what type of instruction each task requires. The guide explains that P and E cores support the same instructions, so a low priority job can run on a P core and a high priority job can run on an E core. The highest priority tasks go to the P cores, but the E cores can step in to do other work when they are not busy.
However, Intel is warning developers against scaling their games to take advantage of all cores. “As the number of threads increases, so does the overhead to manage them,” the guide says, noting that this issue is not specific to Alder Lake. The good news is that Intel says most games work well on the new platform.
“Analysis of games on hybrid architectures has shown that most games perform well, with older or less demanding games favoring the Performance cores. Games already built to make heavy use of multithreading and can be scaled to double digits core numbers, were found to benefit from hybrid architecture because of better throughput,” Intel said.
However, Intel warns of problems with poorly managed tasks. Placing a task on the wrong core can result in a “performance inversion”.
Fortunately, there seems to be a solution. While most games should run well on Alder Lake, some older titles may struggle with the exotic architecture. For this, according to Intel, manufacturers can offer the option to disable the E-cores in the BIOS. We’re not sure if that will be necessary, but the option is there.