Intel Skylake Counters AMD Epyc

　　Intel announced that its Skylake server processors sport an average 65% performance boost over its prior Broadwell chips. Top-end versions of the new Xeon Scalable family nudge ahead of rival AMD’s recently released Epyc CPUs in performance but don’t pack as much I/O.

　　The results suggest that Intel will have no problem maintaining its dominance in the lucrative data center. Nevertheless, AMD’s Epyc and a rising tide of ARM-based server chips from Qualcomm and others are expected to find significant footholds in the broad and diverse cloud computing sector.

　　Platinum 8180 and 8160 versions of Skylake edged AMD’s Epyc 7601 by 2% to 28% in performance and by 12% to 22% in performance/watt on the Specint_rate2006 benchmark. The results could be skewed by Intel’s tendency to use optimized compilers for its benchmarks compared to standard ones that AMD uses.

　　The high-end 8100 series packs 28 cores running at up to 3.6 GHz with up to 48 PCIe 3.0 lanes and six channels of DDR4-2666 memory. By contrast, AMD’s high-end Epyc packs up to 32 cores and all nine of its family support 128 PCI Express 3.0 lanes and eight DDR4-2666 channels.

　　Intel showed tests with two dozen companies, each with different workloads. Results ranged from Skylake beating Broadwell chips by 1.4x for Ansys manufacturing software to 2.2x for apps using Skylake along with Intel’s proprietary Optane solid-state memory drives.

　　The results are “impressive … the increase over Broadwell is much better than they have had in typical generations, especially when you consider [that] these are both 14-nm parts,” said Nathan Brookwood, principal of market watcher Insight64 (Saratoga, California).

　　Skylake edges past AMD's Epyc, but Intel's optimized compilers may skew results in its favor. (Images: Intel)

　　Skylake edges past AMD's Epyc, but Intel's optimized compilers may skew results in its favor. (Images: Intel)

　　“AMD got 25% of the server market when it had a vastly superior product with Opteron, but I don’t think Epyc is vastly better than Skylake,” said Brookwood.

　　Last month, AMD showed a range of benchmarks for Epyc that averaged around 45% more performance than Broadwell. However, the server sector includes a wide range of markets and requirements, many where Intel will have an edge and a few where AMD may score hits.

　　For example, AMD hopes to use its advantage in PCIe and DDR4 to replace dual-socket Broadwell with single-socket Epyc servers. However, Skylake’s new AVX-512 vector processing extensions far outstrip Epyc’s abilities in floating-point intensive jobs.

　　Architecturally, Skylake uses a single processor die with a separate I/O chip. Epyc packs four die in a package including I/O, giving AMD greater flexibility and lower cost at the expense of latency in some operations.

　　Intel has already shipped more than 500,000 of the chips, which are already running in data centers at Alibaba, Amazon, AT&T, and Google. They are in use at more than 30 customers, including a system in Barcelona ranked as the world’s 13th fastest supercomputer.