Action RPG "Atlas Fallen" joins a long line of RPGs this Summer for you to grind into—Baldur's Gate 3, Diablo 4, and Starfield. We've been testing the game for our GPU performance article, and found something interesting—the game isn't optimized for Intel Hybrid processors, such as the Core i9-13900K "Raptor Lake" in our bench. The game scales across all CPU cores—which is normally a good thing—until we realize that not only does it saturate all of the 8 P-cores, but also the 16 E-cores. It ends up with under 80 FPS in busy gameplay at 1080p with a GeForce RTX 4090. Performance is "restored" only when the E-cores are disabled.

Normally, when a game saturates all of the E-cores, we don't interpret it as the game being "aware" of E-cores, but rather "unaware" of them. An ideal Hybrid-aware game should saturate the P-cores for its main workload, and use the E-cores for errands such as processing the audio stack (DSPs from the game), network stack (the game's unique multiplayer network component), physics, in-flight decompression of assets from the disk, etc., which show up in Task Manager as intermittent, irregular load. "Atlas Fallen" appears to be using the E-cores for its main worker threads, and this is found imposing a performance penalty as we found out by disabling the E-cores. This performance penalty is because the E-cores run slower than P-cores, at lower clock speeds, and have much lower IPC, and are cache-starved. Frame data being processed by the P-cores end up having to wait for those from the E-cores, which causes the overall framerate to come down.