The Intel Xeon D Review: Performance Per Watt Server SoC Champion?
by Johan De Gelas on June 23, 2015 8:35 AM EST- Posted in
- CPUs
- Intel
- Xeon-D
- Broadwell-DE
OpenFoam
Computational Fluid Dynamics is a very important part of the HPC world. Several readers told us that we should look into OpenFoam and calculating aerodynamics that involves the use of CFD software.
We use a realworld test case as benchmark. All tests were done on OpenFoam 2.2.1 and openmpi-1.6.3.
We also found AVX code inside OpenFoam 2.2.1, so we assume that this is one of the cases where AVX improves FP performance.
HPC code is where the Xeon E5 makes a lot more sense than the cheaper Xeons. The Xeon E5 is no less than 80% faster with 50% more cores than the Xeon D. In this case, the Xeon D does not make the previous Xeons E3 look ridiculous: the Xeon D runs the job about 33% faster. Let us zoom in.
OpenFoam scales much better on the Xeon E5, and we've seen previously that a second CPU boost performance by 90% offering near linear scaleability. Double the number of cores again and you get another very respectable 60%. Eight cores are 34% faster than four, and 4.1 times faster than one.
Compares this to the horrible scaling of the Xeon E3 v2: 4 cores are slower than one. The Xeon E3 v3 fixed that somewhat, and doubles the performance over the same range. The eight cores of the Xeon D are about 2.8 times faster than one - that is decent scaling but nowhere near the Xeon E5. There are several reasons for this, but the most obvious one is that the Xeon E5 really benefits from the fact that it has almost twice the amount of bandwidth available. To be fair, Intel does not list HPC as a target market for the Xeon D. If the improved AVX2 capabilities and the pricing might have tempted you to use the Xeon D in your next workstation/HPC server, know that the Xeon D can not always deliver the full potential of the 8 Broadwell cores, despite having access to DDR4-2133.
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extide - Tuesday, June 23, 2015 - link
That's ECC Registered, -- not sure if it will take that, but probably, although you dont need registered, or ECC.nils_ - Wednesday, June 24, 2015 - link
If you want transcoding, you might want to look at the Xeon E3 v4 series instead, which come with Iris Pro graphics. Should be a lot more efficient.bernstein - Thursday, June 25, 2015 - link
for using ECC UDIMMs, a cheaper option would be an i3 in a xeon e3 board.psurge - Tuesday, June 23, 2015 - link
Has Intel discussed their Xeon-D roadmap at all? I'm wondering in particular if 2x25GbE is coming, whether we can expect a SOC with higher clock-speed or more cores (at a higher TDP), and what the timeframe is for Skylake based cores.nils_ - Tuesday, June 23, 2015 - link
Is 25GbE even a standard? I've heard about 40GbE and even 56GbE (matching infiniband), but not 25.psurge - Tuesday, June 23, 2015 - link
It's supposed be a more cost effective speed upgrade to 10GbE than 40GbE (it uses a single 25Gb/s serdes lane, as used in 100GbE, vs 4 10Gb/s lanes), and IIRC is being pushed by large datacenter shops like Google and Microsoft. There's more info at http://25gethernet.org/. I'm not sure where things are in the standardization process.nils_ - Wednesday, June 24, 2015 - link
It also has an interesting property when it comes to using a breakout cable of sorts, you could connect 4 servers to 1 100GbE port (this is already possible with 40GbE which can be split into 4x10GbE).JohanAnandtech - Wednesday, June 24, 2015 - link
Considering that the Xeon D must find a home in low power high density servers, I think dual 10 Gbit will be standard for a while. Any idea what 25/40 Gbit PHY would consume? Those 10 Gbit PHYs already need 3 Watt in idle, probably around 6-8W at full speed. That is a large chunk of the power budget in a micro/scale out server.psurge - Wednesday, June 24, 2015 - link
No I don't, sorry. But, I thought SFP+ with SR optics (10GBASE-SR) was < 1W per port, and that SFP+ direct attach (10GBASE-CR) was not far behind? 10GBASE-T is a power hog...pjkenned - Tuesday, June 23, 2015 - link
Hey Johan - just re-read. A few quick thoughts:First off - great piece. You do awesome work. (This is Patrick @ ServeTheHome.com btw)
Second - one thing should probably be a bit clearer - you were not using a Xeon D-1540. It was a ES Broadwell-DE version at 2.0GHz. The shipping product has 100MHz higher clocks on both base and max turbo. I did see a 5% or so performance bump from the first ES version we tested to the shipping parts. The 2.0GHz parts are really close to shipping spec though. One both of my pre-release Xeon D and all of the post-release Xeon D systems was nearly identical.
Those will not change your conclusions but does make the actual Intel Xeon D-1540 a bit better than the one you tested. LMK if you want me to set aside some time on a full speed version on a Xeon D-1540 system for you.