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. 

Actiflow OpenFoam Benchmark

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 1-8 threads

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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  • julianb - Saturday, October 31, 2015 - link

    Thanks for the reply, man.
    And sorry for my late reply, totally forgot about this thread :)
  • eva2000 - Tuesday, June 23, 2015 - link

    Nice... Xeon D-1540 is awesome, but I wish it was clocked 0.2Ghz higher across the board would be just enough to tip that scale versus E5. Did my own benchmarks at https://community.centminmod.com/threads/2864/ :)
  • extide - Wednesday, June 24, 2015 - link

    Thats probably exactly why it ISNT clocked 0.2Ghz higher across the board ;)

    I'm sure Intel wants to see some space between this and E5.
  • boogerlad - Tuesday, June 23, 2015 - link

    If this was marketed for the consumer market with the ability to overclock, this would outsell everything completely. This is what the enthusiast needs!!!
  • Refuge - Tuesday, June 23, 2015 - link

    I don't think this is going to do much of anything for an enthusiast.

    Unless they are interested in building a server for some experiment or project.
  • JohanAnandtech - Wednesday, June 24, 2015 - link

    I still think the i7 59xx series is a better match for consumers: higher clocks and thus ST performance. The Xeon D most interesting features such as integrated 10 GBe and low power don't interest most performance consumers. Most people will have a hard time saturating a 1 GBe line and power savings are not a priority.
  • tspacie - Wednesday, June 24, 2015 - link

    Seems to tick all the boxes for a software development machine. Very good at compilation. Reasonably priced for the performance. Low power. ECC memory. I'm tempted
  • extide - Wednesday, June 24, 2015 - link

    EXACTLY what I was thinking!
  • MrSpadge - Saturday, June 27, 2015 - link

    I would be very tempted by such a chip as well, using it for BOINC. However, Broadwell looses some of the power efficiency advantage if you push it harder, i.e. the largest gains are at low and moderate frequency. Perfect for such server chips and mobile ones, but not so much for people aiming for 4+ GHz.
  • MaxKreimerman - Tuesday, June 23, 2015 - link

    Sounds impresive in just 45w package, but imposible to find in the retail sites such as newegg or wiredzone

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