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Thread: What CPU to use for ABC, and why?

  1. #1
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    What CPU to use for ABC, and why?

    The Project
    The ABC conjecture involves abc-triples: positive integers a,b,c such that a+b=c, a < b < c, a,b,c have no common divisors and c > rad(abc), the so-called radical of abc. The ABC conjecture says that there are only finitely many a,b,c such that log(c)/log(rad(abc)) > h for any real h > 1. The ABC conjecture is currently one of the greatest open problems in mathematics. If it is proven to be true, a lot of other open problems can be answered directly from it. ABC favores 64-bit OS and CPUs

    The Applications
    Linux/x86 2.10
    Linux/x86_64-pc 2.10
    Linux/32-bit PowerPC
    Mac OS X (Intel) 2.10
    Mac OS X (Intel 64-bit) 2.10
    Mac OS X (PowerPC) 2.10
    Windows/x86 2.10
    Windows/x86_64 2.10

    There seem to be no optimized clients that make the best use of the various instruction sets that have been added to CPUs over time.

    The Stats
    Recent top-5 best scoring computers used:
    Opteron 6172 (4x12=48 cores)
    Xeon X5680 (2x6 cores, 24 threads)
    i7-980 (6-core, 12 threads)
    Xeon E5520 (2x4 cores, 16 threads)
    i7-2600K (4-core, 8 threads)

    ABC sure likes you to bring in as much cores as you can support. I'd like to know what a quartet of Opteron 6282SE's would do...That's 64 cores!

    All-time top-5 best scoring computers used:
    Xeon X7350 (4x4=16 cores)
    Xeon E5440 (4 cores, 8 threads)
    Xeon X5470 (2x4=8 cores)
    i7-860 (4 cores, 8 threads)
    Xeon E5520 (2x4 cores, 16 threads)

    WUProp comes with a table showing credit per core per day showing that, while the 8-core FX-8150 Bulldozers do not have the highest scores per core per day, their 8 cores will guarantee a score per CPU per day in the top of the field. Bulldozer is about the level of the Phenom II per core and only slightly worse than the i5 and i7. Overclocking does not help, according to WUProp.

    Highest scores per core per day are for the i5-2500K, using 64-bit Linux. This OS scores significantly higher for this CPU per core per day, around 2500 compared to 1500 for Windows.

    Best performing AMD CPU -per core- is the AMD Phenom II X6 1090T (6 cores, using an OC of 20% to 30%), but 6x 1340 is still less than 8x 1136, so Bulldozer FX-8150 wins the AMD contest. There are no Bulldozers using 64-bit Linux in the database of WUProp yet.
    Last edited by Dirk Broer; 04-26-2012 at 01:17 PM. Reason: xeon x5470 in dual mobo


  2. #2
    NeoGen's Avatar
    NeoGen is offline AMD Users Alchemist Moderator
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    Interesting investigation Dirk.

    It must have been a bit of work to sift through the WUProp database... I think if I were posed that question I would have just said "Any AMD CPU is optimal"

  3. #3
    AMDave's Avatar
    AMDave is offline Seeker of the exit clause Moderator
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    My answer to the question "What CPU to use for ABC, and why?" is - All of them. Because every cycle counts.

    But your point that the client has not yet been optimized where it could have been is a good one.
    The project requires the stability of a client that works the same across the board and they have deliberately chosen to keep it that way.
    Sadly they stopped development through the beta site and with that ended the optimization.
    One or two participants tried in the past to recompile the client their own way and subsequently the project put a stop to that.
    Ultimately, yes the clients could be optimized more than they are, but the project requires the stability of the client in its current form to ensure the cleanliness and reputation of the results.
    So unfortunately, although the client is less than optimal, it is all we have until the project themselves resume their client development work.
    Persuasion did not work. Hence the last client update was 24 Aug 2010 9:56:38 UTC and will likely stay that way for some time to come.
    . . . . . ___
    . . . . . . .\___/\______
    . . . . . . . \__AMD___\\__
    ---------------------------------------------

  4. #4
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    Quote Originally Posted by AMDave View Post
    My answer to the question "What CPU to use for ABC, and why?" is - All of them. Because every cycle counts.
    But given the fact that running 6 systems 24/7 is already the limit, powerbill-wise, I want those 6 CPUs to be as effective as possible.


  5. #5
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    Which AMD Quad would be the best choice for the ABC@Home project, and does it pay to use a hexa- or octocore?

    Scores per day per core:
    Phenom II X4 980: na
    A8-3820: 593.7 (Linux 64)
    A8-3870K: na
    FX-4100: 1317.7 (using Linux 64, Windows 64 brings you 779.9)
    FX-4170: na
    FX-4300: na
    FX-4350: na
    A10-5700: 1,040.9 (Linux 64)
    A10-5800K: na
    A10-6700: na
    A10-6800K: na

    Pretty inconclusive about our quaddies. Best scoring AMD CPU appears now the FX-8350 with 1,502.5 per core per day (=12,020 per CPU/day). The i7-3770K is only slightly better at 2,089.0 per thread/day (=16,712 per CPU/day) and twice as expensive to purchase (though less expensive to run 24/7).
    Last edited by Dirk Broer; 01-15-2014 at 11:12 PM.


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