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Hyperthreading with folding

Discussion in 'Team OcUK Distributed Computing Projects' started by lucifersam, 17 Jun 2006.

  1. lucifersam

    Gangster

    Joined: 18 May 2006

    Posts: 474

    Location: Somewhere South

    Yes its yet another question from Lucifersam
    I have a 3.2GHz P4E prescott and was wondering if i should use two clients, would i still get the same type of work units or would it affect how accurate the results were, i have looked around and found conflicting answers cheers
     
  2. BillytheImpaler

    Man of Honour

    Joined: 2 Aug 2005

    Posts: 8,741

    Location: Cleveland, Ohio, USA

    You can run a WU on each logical CPU without problems. Stanford officially discourages it becasue it means that each WU will take longer to complete. However, you can get an extra 20% points increase but using HT to run two at once. Make your decision based on that.

    Keep in mind that with 2 WUs running the amount of memory required will scale along with tehe doubled work.
     
  3. SiriusB

    Capodecina

    Joined: 16 Dec 2005

    Posts: 14,448

    Location: Manchester

    Just stick with one client and let us big boys with the real dual core CPUs run two clients :p








    Im only messing. :D

    SiriusB
     
  4. lay-z-boy

    Sgarrista

    Joined: 27 Sep 2004

    Posts: 9,231

    Location: Nantwich

    Hyperthreading is faster in the long run than a single thread, due to the fact you get 2 wu's at 1.5 times the time it would take to do 1, 1 after the other, so for a single wu its fast but if you are going for a long run it is better, expect a 10-15% boost in output. :)
     
  5. MGP

    Mobster

    Joined: 24 Oct 2004

    Posts: 2,583

    Location: Surrey

    But, if you have your PC hyperthreading enabled, yet only allow one Wu at a time, will all or only 1/2 of your CPU's total power get used? Boinc certainly only uses 50% of power so half your CPU goes to waste.
     
  6. rich99million

    Sgarrista

    Joined: 26 Dec 2002

    Posts: 9,348

    Location: Derbyshire

    It will show as only 50% in task manager due to the way windows treats HT like dual processors.
    I would imagine it's using more like 80% of the chip.

    I guess the best way to check is to bench it once with HT and once without HT enabled and see what you get for each
     
  7. lay-z-boy

    Sgarrista

    Joined: 27 Sep 2004

    Posts: 9,231

    Location: Nantwich

    hyperthreading is a 'few' extra transistors on a physical core to create a virtual core, to be used, the logical core uses unused parts of the physical core along with a small amount of used parts so it makes the structure more 'efficant'.
    So if it says 50% is being used and you have allowed windows to auto level it out then its shouldnt be any slower.
    So 50% should be as fast as single core usage even if it split.

    Boinc, when i used it ages ago, had an option to allow multi cores so it should use all 100% if you set it up right.
     
  8. lucifersam

    Gangster

    Joined: 18 May 2006

    Posts: 474

    Location: Somewhere South

    Ive tried my CPU as suggested with HT on and off using 1 client, seems faster with HT on because when I start using the computer it does not slow down the process due to some of the spare cpu not being used. I think im actually gonna stick to that setup cause using two cleints seems to bump up the core tem (its already crazy 70+ in this heat) and uses more leccy cheers for your help guys