Cost Analysis - An x86 Massacre

The Graviton2 showcased that it can keep up extremely well in terms of performance and throughput, even beating the competition in a lot of the tests. However sometimes you don’t care too much about performance, and you just want to get some workload completed in the cheapest way possible, at which point value comes into play.

Amazon does allude to that, stating that the new chip is able to achieve 40% better performance per dollar than its competition. As covered in the introduction, for the 64-vCPU count 16xlarge instances the m6g (Graviton2), m5a (EPYC1), and m5n (Xeon Cascade Lake) are priced at an hourly cost of $2.464, $2.752 and $3.808 respectively.

Translating the time to completion of our various SPEC tests to hours and multiplying by the hourly cost, we end up with a cost per fixed workload metric:

An aggregate of all workloads summed up together, which should hopefully end up in a representative figure for a wide variety of real-world use-cases, we do end up seeing the Graviton2 coming in 40% cheaper than the competing platforms, an outstanding figure.

If we were to compare the same fixed workload at smaller instance counts, because of Graviton2’s better per-thread performance, we’re seeing even better results on 4xlarge (16 vCPUs) instances. Here the Amazon chip showcases 43% better value than the Xeon chip, and beats the AMD instances by being 53% cheaper.

If we were to transform the results into a fixed throughput per dollar metric, we again see the Graviton2 far ahead. The unit here is SPEC runs per dollar.

The lower the vCPU instance size, the better value the Graviton2 seemingly becomes, as its performance with increased vCPUs scales sublinearly, but the cost of bigger vCPU instances scales linearly, an effect that’s almost not present at all in the AMD system, and only marginally present in the Xeon instances.

Again, the Graviton2’s scaling here might differ in production instances, but given that you can’t just chop off half the chip (or have access to only one of two sockets, in Intel’s case here) and that Amazon seemingly isn’t doing any static partitioning of the chip’s shared resources, I do think it’s more likely than not that such performance and value figures will be encountered in the real-world.

Even ignoring the lower vCPU instances, Amazon was able to deliver on its promise of 40% better performance per dollar, and it’s a massive shakeup for the AWS and EC2 ecosystem.

SPEC - MT Performance (4xlarge 16 vCPU) Conclusion & End Remarks


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  • Sahrin - Tuesday, March 10, 2020 - link

    I may be remembering incorrectly, but doesn't Gen 1 Epyc have the same cache tweaks as Zen+ (ie, Epyc 7001 series is based on Zen+, not Zen)? Reply
  • Rudde - Wednesday, March 11, 2020 - link

    They have same optimisations as first gen Zen APUs, i.e. Ryzen mobile 2xxx. Zen+ is a further developed architecture, albeit without further cache tweaks.
    The cache tweaks in question were meant to be included in the origina Zen, but didn't make it in time. As such one could argue that first gen Ryzen desktop is not full Zen (1), but a preview.
  • Sahrin - Tuesday, March 10, 2020 - link

    The fact that Amazon refused to grant access to Rome-based instances tells you everything you need to know. Graviton competes with Zen and Xeon, but is absolutely smoked by Zen 2 in both absolute terms and perf/watt.

    It's a shame to see Amazon hide behind marketing bullshit to make its products seem relevant.
  • rahvin - Thursday, March 12, 2020 - link

    Don't be silly. Amazon buys processors in the thousands. There is no way AMD could have supplied enough Rome CPU's to Amazon to load up an instance at each of their locations in the time Rome has been for sale.

    It typical takes about 6 months before Amazon gets instances online because AMD/Intel aren't going to give Amazon the entire production run for the first 3 months. They've got about 20 data centers and you'd probably need several hundered per data center to bring an instance up.

    Consider the cost and scale of building that out before you criticize them for not having the latest and greatest released a month a go. Rome hasn't been available to actually purchase for very long and the Cloud providers get special models and AMD still needs to supply everyone else as well.
  • eastcoast_pete - Tuesday, March 10, 2020 - link

    While I am currently not in the market for such cloud computing services aside from maybe some video processing, I for one welcome the arrival of a competitive non-x86 solution! Can only make life better and cheaper when and if I do. Also, ARM N1 arch lighting a fire under the x86 makers in their easy chairs will keep AMD and Intel on their feet, and that advance will filter down to my future desktops and laptops. Reply
  • eastcoast_pete - Tuesday, March 10, 2020 - link

    Thanks Andrei! Just out of curiosity, that "noisy neighbor" behavior you saw on the Xeon? I know it's mostly speculation, but would you expect this if someone is running AVX512 on neighboring cores? AVX512 is very powerful if applications can make use of it, but things get very toasty fast. Care to speculate? Reply
  • willgart - Tuesday, March 10, 2020 - link

    where are the real life benchmarks???
    video encoding / decoding ?
    database performance ?
    web performance ?
    https encryption ?
  • The_Assimilator - Thursday, March 12, 2020 - link

    Agreed 100%. Without figures of actual real-world applications compiled with actual real-world compilers handling actual real-world workloads, this essentially amounts to an advertorial for Amazon, Graviton2 and Arm. Reply
  • Danvelopment - Wednesday, March 11, 2020 - link

    This may sound stupid as I'm just getting into AWS as backup throughput for local servers on my web project that releases April.

    "If you’re an EC2 customer today, and unless you’re tied to x86 for whatever reason, you’d be stupid not to switch over to Graviton2 instances once they become available, as the cost savings will be significant."

    How do you know whether what you're using is Intel, AMD or Graviton(1/2)? (I'm using T2s right now with no weighting and if our release gets hit hard, will give it weight and and increase its capacity).

    As they're not actually doing anything, then I'd have no issue switching over, but can't tell what I'm on.
  • CampGareth - Wednesday, March 11, 2020 - link

    There's a list here:

    If you're on T2 instances you're on Intel chips at the moment.

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