"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. 

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  • extide - Tuesday, July 11, 2017 - link

    PCPer made this same mistake -- Nehalem/Westmere used a crossbar memory bus -- not a ringbus. Only Nehalem/Westmere EX used the ringbus (the 6500/7500 series) The i7 and Xeon 5500 and 5600 series used the crossbar.
  • extide - Tuesday, July 11, 2017 - link

    Sandy Bridge brought the ringbus down to Xeon EP and client chips.
  • Yorgos - Tuesday, July 11, 2017 - link

    "With the complexity of both server hardware and especially server software, that is very little time. There is still a lot to test and tune, but the general picture is clear."

    No wonder why we see ubuntu and ancient versions of gcc and the rest of the s/w stack.
    Imagine if you tried to use debian or rhel, it would take you decades to get the review.
  • eligrey - Tuesday, July 11, 2017 - link

    Why did you omit the Turbo frequencies for the Xeon Gold 6146 and 6144?

    Intel ARK says that the 6146's turbo frequency is 4.2GHz and the 6144's is 4.5GHz.
  • eligrey - Tuesday, July 11, 2017 - link

    Oops, I mean 4.2GHz for both.
  • boozed - Tuesday, July 11, 2017 - link

    Need more Skylake-SP SKUs
  • rHardware - Tuesday, July 11, 2017 - link

    For the purley system, It's listed that you used Chipset Intel Wellsburg B0

    This information cannot be correct. Lewisburg Chipset is the name of the purley chipset. Also, B0 stepping lewisburg also wouldn't boot with the stepping of CPU you have.
  • rHardware - Tuesday, July 11, 2017 - link

    That 0200011 microcode is also very old.
  • Rickyxds - Tuesday, July 11, 2017 - link

    I'am a brazilian processors enthusiast and I'am very critic about intel and AMD processors, between 2012 and Q1 2017 AMD just doesn't existed, who bought AMD on that years, bougth just for love AMD and just it, doesn't for the price, doesn't for the high core count, doesn't for AMD is red, AMD was the worst performance processors. The A9 Apple dual core performance is better than FX 8150.

    But now I am very surprise with the aggressive AMD prices. No one here Imagined get the Ryzen 7 performance for less than $500. And I don't know if this scenario brings profit to AMD, but for the image against the intel it's wonderful.

    On the next years we will see.
  • krumme - Tuesday, July 11, 2017 - link

    Thank you for quality stuff article especially given the short time. So thank you for booting up Johan !

    Interesting and surpricing results.

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