AMD EPYC Milan Review Part 2: Testing 8 to 64 Cores in a Production Platform

SPEC - Multi-Threaded Performance - Subscores

Picking up from the power efficiency discussion, let’s dive directly into the multi-threaded SPEC results. As usual, because these are not officially submitted scores to SPEC, we’re labelling the results as “estimates” as per the SPEC rules and license.

We compile the binaries with GCC 10.2 on their respective platforms, with simple -Ofast optimisation flags and relevant architecture and machine tuning flags (-march/-mtune=Neoverse-n1 ; -march/-mtune=skylake-avx512 ; -march/-mtune=znver2 (for Zen3 as well due to GCC 10.2 not having znver3). 

I’ll be going over two chart comparisons, first of all, with the respective flagship parts, consisting of the new EPYC 7763 numbers, pitted against Intel’s 40-core Xeon Ice Lake SP and Ampere’s Altra Q80-33, along with the figures we have on AMD’s EPYC 7742. It’s to be noted that this latter is a 225W part, compared to the 280W 7763.

In SPECint2017, the EPYC 7763 extends its lead over Intel’s current best CPU, improving the numbers beyond what we had originally published in our April review. While AMD also further narrows the gap to Ampere’s 80-core Altra SKU, there are still many core-bound workloads that still notably favour the Neoverse N1 part given its 25% advantage in core count.

Also in SPECint2017, but this time focusing on the mid-tier SKUs, the main comparison points that are interesting here is the new 24-core EPYC 7443 and 16-core EPYC 7343 against the new 28-core Xeon 6330. What’s shocking here, is that Intel’s new Ice Lake SP server chip has troubles not only competing against AMD’s 24-core chip, but actually even struggles to differentiate itself from AMD’s 16-core chip, which is quite shocking.

The 72F3 8-core part is interesting, but generally we have troubles to competitively place such a SKU given that we don’t have a comparable part from the competition to pit against it.

For the high-end SKUs, we again see the 7763 increase its performance positioning compared to what we had review a few months ago, although with fewer large performance boost outliers, due o the memory-heavy nature of the floating-point test suite.

In the low-end SKUs, we see a similar story as in the integer suite, where AMD’s 16-core 7343 battles it out against Intel’s 28-core Xeon, while the 24-core unit is comfortable a good margin ahead of the competition.

The 72F3 showcases some interesting score here – because there’s more workloads that are fundamentally memory bound; the actual core count deficit of this SKU doesn’t really hamper its performance compared to its siblings. If anything, the lower core count actually has some positive side-effects as it results in less cache and DRAM contention, resulting in less overhead and actually higher performance than the higher core count parts. Theoretically you could mimic this with the higher core count parts by simply running fewer workload instances and threads, but if a system deployment would be running workloads that are more typical of such performance characteristics, the low-core count 72F3 could make sense.