On-chip cache memory is critical for performance, because main memory is relatively slow compared to CPU clock speed. That’s why high performance CPUs always have more cache memory than consumer CPUs.
- Apple states 4.4 GHz Turbo Boost for the 16/24/28 core CPUs, vs 4.6 GHz in the Intel specifications, about a 5% difference.
- Cache memory is considerably larger as stated by Apple than Intel specifications state.
UPDATE: reader Martin P remarks that “Apple just added the L2 Cache 1MB per Core to the Level3 Cache Intel is stating”; see Wikichip.org.
UPDATE: looks like the 4.4 GHz vs 4.6 GHz difference is “Max Turbo Frequency” vs “Intel® Turbo Boost Max Technology 3.0 Frequency”, the latter being a few cores that happen to be a bit better than the others. It is unclear if macOS supports scheduling on these particular cores.
8-Core 16t 3.5GHz Intel Xeon W-3223 Turbo Boost up to 4.0GHz,
16.5MB 24.5MB cache
12-Core 24t 3.3GHz Intel Xeon W-3235 Turbo Boost to 4.4GHz,
19.25MB 31.25MB cache
16-Core 32t 3.2GHz Intel Xeon W-3245 Turbo Boost to
4.6 4.4GHz, 22MB 38MB cache
24-Core 48t 2.7GHz Intel Xeon W-3265M Turbo Boost to
4.6 4.4GHz, 33MB 57MB cache
28-Core 56t 2.5GHz Intel Xeon W-3275M Turbo Boost to
4.6 4.4GHz, 38.5MB 66.5MB cache
Are Apple’s specifications wrong, or does Apple use some special chip variant?
Including lots more cache memory might raise chip price significantly, given that the yield of chips with a lot more cache might be lower.