Avantek's Arm Workstation: Ampere eMAG 8180 32-core Arm64 Review
by Andrei Frumusanu on May 22, 2020 8:00 AM ESTSPEC2006 & 2017: Weak ST Performance
Of course, while maybe the individual cores might not be all that performant, the chip employs 32 of them. Together with the 32MB L3 cache as well as the 8-channel DDR4-2666 memory interface certainly the system should be able to showcase better multi-core results.
Indeed, the chip does better in the tests, at least more often than not being able to beat the consumer-grade Intel CPU. The performance scaling of the eMAG system also isn’t bad at all – scaling from 1 core to 32 cores sees the performance scale with an average factor of 0.73x per core, and a median per SPEC2006 and 2017 test of 0.78x; that’s much better scaling than Amazon’s Graviton2 when scaling ST performance to its full 64 cores.
Still, the MT results, while beating the Intel system, still don’t look all that great when considering the fact that we’re talking about 8 cores vs 32 cores. A 400% advantage in cores for only a 30% performance advantage.
The Graviton2 naturally eclipses both comparisons here, and the only reason to consider this chip’s figures is that Ampere’s upcoming Altra processor with 80 cores and 3GHz should be notably faster than the Amazon chip.
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SarahKerrigan - Friday, May 22, 2020 - link
The X-Gene microarchitecture was never particularly stellar and by the time eMag rolled around it was woefully obsolete. I did some testing on eMag a few months back and it was pretty dire. When I spent some time on Graviton2 last week, it was like night and day compared to eMag (frequently 2+ times the single-thread perf despite a much lower clock), so I have high hopes for Altra.SarahKerrigan - Friday, May 22, 2020 - link
By the way, Andrei, you may want to correct the ST SPECFP subtest result graph - it looks like you used Graviton as a template and forgot to change the labels to eMag, because right now it only mentions Graviton1, and Graviton2, and Intel, not eMag.Andrei Frumusanu - Friday, May 22, 2020 - link
Thanks, good catch.Flunk - Friday, May 22, 2020 - link
Interesting to see even if this hardware only makes sense for very specialized purposes. ARM processors have gone from only applicable to mobile devices to something that would have made sense in a server a few years ago.SarahKerrigan - Friday, May 22, 2020 - link
This isn't exactly a good representative of ARM processors; chips like Graviton2 are competitive for server workloads today, and make eMag look like a toy by comparison.eastcoast_pete - Friday, May 22, 2020 - link
Thanks Andrei, good and in-depth review! You and others here have already commented on the great difference of this legacy CPU to Ampere's Altra or Amazon's Graviton 2. What I am also very curious about is Fujitsu's ARM-based multicore CPU (A64FX). Amongst other features, it supports 512-bit scalable vector extensions (SVEs), so same width as Intel's AVX512. I wonder if someone at Fujitsu reads Anandtech, and maybe send you a setup for review, although a PRIMEHPC might be out of the scope here. Still, that's an ARM v8 design that should beat the Graviton 2 and the Altra, especially if applications can make use of the wide SVEs.anonomouse - Friday, May 22, 2020 - link
Based on what we know of the A64FX, it’ll almost certainly *only* beat Graviton 2/Altra in cases where it can heavily utilize wide vectors. In all other scenarios it really doesn’t have a lot of execution width, and only runs at 2.2Ghz. The disclosures in their Microarchitecture guide also don’t showcase anything impressive looking on the branch predictor, which is fine for the typical HPC workloads it will run. That thing is very heavily purpose designed for HPC, and it’s clear they focused on that and not general performance.SarahKerrigan - Friday, May 22, 2020 - link
Indeed. It's a specialized chip. I would expect no miracles from it on general-purpose loads.eastcoast_pete - Friday, May 22, 2020 - link
Agree with you and anonomouse on general purpose loads; my interest in wide vectors is mainly due to their utility for video processing and encoding, if (!) the software supports it. For those applications, AVX512 is what keeps Intel competitive with EPYCs in the x64 space. As a question, is anything like an AV1 encoder even available for ARM v8, and specifically to use wide SVEs?Wilco1 - Saturday, May 23, 2020 - link
There are many AV1 codecs which have AArch64 optimizations, but most focus on older mobile phone cores (eg. http://www.jbkempf.com/blog/post/2019/dav1d-0.5.0-... ), so likely need further work on latest microarchitectures with up to 4 128-bit Neon pipes.It's early days for SVE, the first version (as in A64FX) is aimed at HPC. Video codecs will be optimized for SVE2 when hardware becomes available.