February 8, 2026
E-cores vs P-cores: comment war!
Why E cores make Apple Silicon fast
Tiny quiet cores keep Macs snappy — fans cheer, skeptics grumble
TLDR: Apple’s efficiency cores keep background chores off the fast cores, making Macs feel snappy. Commenters split between benchmark bragging, complaints about runaway indexing and sync, and devs asking how macOS decides which core runs what — a debate that matters for real-world speed and sanity.
Apple’s latest chips split work between fast “performance” cores (P) and power-saving “efficiency” cores (E). The article says E cores are the unsung heroes: they chew through background chores like Spotlight indexing, iCloud sync, and Siri so your apps stay smooth. Think noisy roommates confined to the back room. The comments lit up. tyleo waved benchmarks, insisting the P cores “kick butt” and M‑series laptops outrun high‑end Windows desktops, linking his test. amelius called it smart framing: move slow stuff to slow cores, keep fast cores free.
Then the skeptics showed up with beachball PTSD. ricardobeat said “2,000 threads in 600 processes” isn’t “good news” when Spotlight or iCloud goes rogue, and warned things feel “out of hand.” roomey asked the uncomfortable question: are we comparing Apple Silicon to old Intel Macs or to modern Linux laptops that feel fine even with corporate bloat? Meanwhile, devs like drob518 poked the mysterious macOS scheduler and its Quality of Service tags (Apple’s way to label foreground vs background), asking how threads land on E vs P cores. The vibe: fans cheer the E‑core cleanup crew; skeptics say the background zoo still bites; engineers want receipts and transparency.
Key Points
- •Apple Silicon Macs use Efficiency cores to absorb background tasks, preserving Performance cores for foreground applications.
- •During startup, E cores show high utilization from services like Spotlight indexing, Time Machine, and XProtect Remediator, while P cores remain largely idle.
- •macOS employs Quality of Service (QoS) to classify threads, allocating foreground work to P cores and restricting background threads from P cores.
- •QoS existed since OS X 10.10 Yosemite and differs from traditional Posix nice priorities by separating foreground and background execution.
- •Tools like App Tamer and taskpolicy cannot promote background threads to P cores, evidencing enforced scheduling that improves responsiveness and battery life.