Memory Subsystem: Bandwidth

Bandwidth is of course measured with John McCalpin's Stream bandwidth benchmark. We compiled the stream 5.10 source code with gcc 5.2 64 bit. The following compiler switches were used on gcc:

-Ofast -fopenmp -static -DSTREAM_ARRAY_SIZE=120000000

The latter option makes sure that stream tests with array size which are not cacheable by the Xeon's huge L3-caches nowadays.

Stream Triad w Gcc

The ThunderX keeps up with the midrange Xeon E5s. The relatively low numbers might surprise a lot of people, as Stream benchmarks now hit 100 GB/s and beyond easily these days. First of all, these are of course single socket measurements, as opposed to the typical dual socket stream tests. Secondly, only the "high-end" and "segment optimized" Intel SKUs support DDR-2400, many SKUs are "limited" to DDR4-2133. With DDR4-2400, Xeon E5's score would increase to 48 GB/s per socket.

Last but not least: we do not use the icc compiler. Using the icc compiler boosts the performance of this benchmark by 33% (to 64 GB/s). That raw bandwidth is most likely only useful in some AVX-optimized HPC applications, a market that the ThunderX does not target. So far, so good: the ThunderX memory controller delivers twice as much bandwidth as Intel's Xeon D SoC. It is the first time the Xeon D gets beaten by an ARM v8 SoC...

Selecting the Competition & System Configurations Memory Subsystem: Latency Measurements
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  • JohanAnandtech - Wednesday, June 15, 2016 - link

    Good suggestion. I have been using an ipmi client to manage several other servers, like the IBM servers. However, such a GUI client is still a bit more userfriendly, ipmi commands can get complicated if you don't use them regularly. The thing is that HP and Intel's BMC GUI are a lot easier to use and more reliable.
  • fanofanand - Wednesday, June 15, 2016 - link

    I think you may have an inaccurate figure of 141 at idle (in the graph) for the Thunder. "makes us suspect that the chip is consuming between 40 and 50W at idle, as measured at the wall"
  • JohanAnandtech - Wednesday, June 15, 2016 - link

    If you look at the Column "peak vs idle", you see 82W. At peak, we assume that a 120W TDP chip will probably need about 130W. 130W - 82W (both measured at the wall) = 50W for the SoC alone at idle measured at the wall, so anywhere between 40-50W in reality. My Calculation is a "guestimate", but it is clear that the Cavium chip needs much more in idle than the Intel chips.(10-15W) .
  • djayjp - Wednesday, June 15, 2016 - link

    Many spelling/grammar issues here. It impacts readability. Please read before posting.
  • djayjp - Wednesday, June 15, 2016 - link

    That is to say in the article.
  • mariush - Wednesday, June 15, 2016 - link

    These guys are already working on ThunderX2 (54 cores, 3 Ghz , 14nm , ARMv8) and they already have functional chips : https://www.youtube.com/watch?v=ei9uVskwPNE
  • Meteor2 - Thursday, June 16, 2016 - link

    It's always jam tomorrow, isn't it? Intel is working on new chips too, you know.
  • beginner99 - Wednesday, June 15, 2016 - link

    It loses very clearly in performance/watt to Xeon-D. In this segment the lower price doesn't matter in that case and the fact that it has a process disadvantage doesn't matter either. What counts is the end result. And I doubt it would cost $800 if made on 14/16nm. I mean why would anyone buying this take the risk? Safer bet to go with Intel also due to more flexible use (single and multi threaded). The latency issue is mentioned but downplayed.
  • blaktron - Wednesday, June 15, 2016 - link

    So downplayed. Anandtech desperately wants ARM servers, but its a solution looking for a problem. Big web front ends running on bare metal are such a small percentage of the server market that developing for it seems stupid. Xeon-D was already in development for SANs, they just repurposed it for docker and nginx.
  • Senti - Wednesday, June 15, 2016 - link

    Very nice article. I especially liked the emphasis on relations of test numbers and real world workloads and what was problematic during the testing.

    It would be great to see the same style desktop CPU review (Zen?) form you instead of mix of reprinted marketing hype with silly benchmark numbers dump that plagues this site for quite some time now.

    Some annoying typos here and there, like "It is clear that the ThunderX is a match for high frequency trading", but nothing really bad.

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