"It looks the same on the powerpoint slide, but they are very different". The place is Austin, where an AMD engineer is commenting on the slides describing the Zen and Skylake schematics. In Portland, the Intel representatives could not agree more: "the implementation matters and is completely different". "We have to educate our customers that they can not simply compare AMD's 32 core with our 28 cores".

This morning kicks off a very interesting time in the world of server-grade CPUs. Officially launching today is Intel's latest generation of Xeon processors, based on the "Skylake-SP" architecture. The heart of Intel's new Xeon Scalable Processor family, the "Purley" 100-series processors incorporate all of Intel's latest CPU and network fabric technology, not to mention a very large number of cores.

Meanwhile, a couple of weeks back AMD soft-launched their new EPYC 7000 series processors. Based on the company's Zen architecture and scaled up to server-grade I/O and core counts, EPYC represents an epic achievement for AMD, once again putting them into the running for competitive, high performance server CPUs after nearly half a decade gone. EPYC processors have begun shipping, and just in time for today's Xeon launch, we also have EPYC hardware in the lab to test.

Today's launch is a situation that neither company has been in for quite a while. Intel hasn't had serious competition in years, and AMD has't been able to compete. As a result, both companies are taking the other's actions very seriously.

In fact we could go on for much longer than our quip above in describing the rising tension at the headquarters of AMD and Intel. For the first time in 6 years (!), a credible alternative is available for the newly launched Xeon. Indeed, the new Xeon "Skylake-SP" is launching today, and the yardstick for it is not the previous Xeon (E5 version 4), but rather AMD's spanking new EPYC server CPU. Both CPUs are without a doubt very different: micro architecture, ISA extentions, memory subsystem, node topology... you name it. The end result is that once again we have the thrilling task of finding out how the processors compare and which applications their various trade-offs make sense.

The only similarity is that both server packages are huge. Above you see the two new Xeon packages –with and without an Omni-Path connector – both of which are as big as a keycard. And below you can see how one EPYC CPU fills the hand of AMD's CEO Dr. Lisa Su. 

Both are 64 bit x86 CPUs, but that is where the similarities end. For those of you who have been reading Ian's articles closely, this is no surprise. The consumer-focused Skylake-X is the little brother of the newly launched Xeon "Purley", both of which are cut from the same cloth that is the Skylake-SP family. In a nutshell, the Skylake-SP family introduces the following new features: 

  1. AVX-512 (Many different variants of the ISA extension are available)
  2. A 1 MB (instead of a 256 KB) L2-cache with a non-inclusive L3
  3. A mesh topology to connected the cores and L3-cache chunks together

Meanwhile AMD's latest EPYC Server CPU was launched a few weeks ago:

On the package are four silicon dies, each one containing the same 8-core silicon we saw in the AMD Ryzen processors. Each silicon die has two core complexes, each of four cores, and supports two memory channels, giving a total maximum of 32 cores and 8 memory channels on an EPYC processor. The dies are connected by AMD’s newest interconnect, the Infinity Fabric...

In the next pages, we will be discussing the impact of these architectural choices on server software. 

AMD's EPYC Server CPU
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  • Headley - Friday, July 14, 2017 - link

    I thought the exact same thing Reply
  • JKflipflop98 - Wednesday, July 12, 2017 - link

    For years I thought you were just really committed to playing the "dumb AMD fanbot" schtick for laughs. It's infinitely more funny now that I know you've actually been *serious* this entire time. Reply
  • ddriver - Wednesday, July 12, 2017 - link

    Whatever helps you feel better about yourself ;) I bet it is funny now, that AT have to carefully devise intel biased benches and lie in its reviews in hopes intel at least saves face. BTW I don't have a single amd CPU running ATM. Reply
  • WinterCharm - Thursday, July 13, 2017 - link

    Uh, what are you smoking? this is a pretty even piece. Reply
  • boozed - Tuesday, July 11, 2017 - link

    You haven't done your job properly unless you've annoyed the fanboys (and perhaps even fangirls) for both sides! Reply
  • JohanAnandtech - Wednesday, July 12, 2017 - link

    Wise words. Indeed :-) Reply
  • Ranger1065 - Wednesday, July 12, 2017 - link

    If you are referring to ddriver, I agree, wise words indeed. Reply
  • ddriver - Wednesday, July 12, 2017 - link

    Well, that assumption rests on the presumption that the point of reviews is to upsed fanboys.

    I'd say that a "review done right" would include different workload scenarios, there is nothing wrong with having one that will show the benefits of intel's approach to doing server chips, but that should be properly denoted, and should be just one of several database tests and should be accompanied by gigabytes of databases which is what we use in real world scenarios.
    Reply
  • CoachAub - Wednesday, July 12, 2017 - link

    It was mentioned more than once that this review was rushed to make a deadline and that the suite of benchmarks were not everything they wanted to run and without optimizations or even the usual tweaks an end-user would make to their system. So, keep that in mind as you argue over the tests and different scenarios, etc. Reply
  • ddriver - Thursday, July 13, 2017 - link

    It doesn't take a lot of time to populate a larger database so that you can make a benchmark that involves an actual real world usage scenario. It wasn't the "rushing" that prompted the choice of database size... Reply

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