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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Kjella - Tuesday, June 23, 2015 - link
Server on a chip? It's not intended for use with a display, it does all it's "supposed to" do for the hyperscale market without any display.close - Tuesday, June 23, 2015 - link
"Intel was able to combine 8 of them together with dual 10 Gbit, 4 USB 3.0 controllers, 6 SATA 3 controller and quite a bit more".This ^^ makes it a SoC. Ok, a video output would be nice but that certainly doesn't disqualify it.
ats - Tuesday, June 23, 2015 - link
cause video isn't required or even wanted in this market segment. It is a SoC, which simply means system on a chip and doesn't have some ironclad definition. Hell, most "SoC" chips aren't really systems on a chip anyways and require significant supporting logic (this is true for just about any cell phone SoC on the market too).bill.rookard - Tuesday, June 23, 2015 - link
Exactly, you would tend to use remote management over the network to admin this type of a unit. I have several rackmounted servers in my basement (I do some home-serving of websites over a business class connection) and while I do have them actually hooked up to a display, I can hardly remember the last time I looked at them as 99.9% of the time I SSH into everything for administration.About the only time you'd ever really use a display is if you were doing multiple VMs of assorted types. Beyond that, it's wattage wasted.
ats - Tuesday, June 23, 2015 - link
Yeah honestly, having several SM boards with their ILM system, the only time I'd ever hook up a display is if the network was down. The SM ILM will fully proxy pretty much anything you want and give you a 1200p display that works for just about anything. And you can remotely hook up CDs, DVDs, BRs, USB, etc through it along with the stand console and keyboard/mouse functions. Its a very nice solution.nightbringer57 - Tuesday, June 23, 2015 - link
Basically, you don't need video output.Even if you do, mainboard manufacturers usually include a third-party chip with dedicated functions that, along other things, provide a VGA port usable for a server use.
In this case, the AST2400 chip offers some basic GPU functions with a VGA port along with many remote control-related stuff.
Adding all those functions to the Intel SoC would be awfully expensive. The chip only requires a simple PCIe x1 connection from the SoC, but provides hundreds of additional pins. Not only would those functions probably be hard to implement on a relatively recent 14nm process, but it would require at least 300 new pins on the SoC to add all the 3rd party chip's functions on it, which is almost impossible to do.
Th-z - Tuesday, June 23, 2015 - link
There doesn't seem to have a concrete definition for the term SoC, but it's ridiculous now with the term SoC bandwagon. Everything seems to be called "SoC" these days as long as a chip has more than one functions integrated. One of examples is people even called current console's integrated CPU and GPU chip as SoC, which doesn't even have networking and other peripheral units in it. When a system has so many "SoCs" inside, the term really has lost its meaning and significance.redzo - Tuesday, June 23, 2015 - link
I'm thinking this is a bad name for a product like this. It reminds of the infamous Celeron D and Pentium D line.nandnandnand - Tuesday, June 23, 2015 - link
Anyone who can figure out Xeon D exists can probably tell the differencewussupi83 - Tuesday, June 23, 2015 - link
I agree with redzo, I think anyone who can figure out a 'Xeon D' exists AND remembers that Pentium & Celeron D's existed would initially assume this is a budget Xeon - which it's clearly not. E4 sounds pretty logical. But sure lets just put D...