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The architecture of P cores and E cores are different. A 2 GHz P core isn't necessarily slower than a 2.2 GHz E core. It's like comparing a Pentium 4 with a Cor
by theandrewbailey 2y ago
The architecture of P cores and E cores are different. A 2 GHz P core isn't necessarily slower than a 2.2 GHz E core. It's like comparing a Pentium 4 with a Core 2 using only clockspeed: it can't be done.
You point out a 144 E core Xeon and a 128 P core Xeon. The 128 core chip has a much higher TDP, so it's possible that it's way faster than the 144 core one. It's not burning electricity because it's fun: doing things faster tends to cost more power.
There's also the big question of what kind of workload you're intending to run. Some are heavily threaded, so the E cores might be faster. Others are not as threaded or are sensitive to processing latency, so the P cores might be faster.
- highfrequency 2y agoStill, we need some way to compare the per-core performance if not the clock speed. I guess you’re suggesting that IPC is significantly higher in the P Cores? Is there evidence for this? Besides hyperthreading (which always seemed like mostly a gimmick), some portions of AVX-512 (which most people never use), and a bigger cache - in what concrete ways are the P Cores much faster?
- theandrewbailey 2y agoThe only way to compare them is to run benchmarks on them and compare the results. This would also pick up on other things that can impact performance, like memory, I/O, and other software optimizations. Yes, I'm suggesting that p-cores have more IPC. Each e-core occupies a much smaller area on the CPU die and uses far fewer transistors, and are claimed to have Skylake (~10 year old CPU architecture) levels of IPC. There are some very real drawbacks to build a core that uses less power than others. Also: https://www.techpowerup.com/review/intel-core-i9-12900k-e-cores-only-performance/ https://www.techpowerup.com/review/intel-core-i9-12900k-e-co...