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Thread: WU correlation to core usage |
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Thread Status: Active Total posts in this thread: 4
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kcharuso
Cruncher Joined: Jun 3, 2013 Post Count: 7 Status: Offline Project Badges: 
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hi all,
----------------------------------------i was wondering the differences in results an overclock and various cpu core count would make so i collected a few data and the result is in an excel. i hope my calculations are correct but it did not make much sense to me. it seems like using less cores to compute finish more wu. if so, there is no need to rely on expensive CPU with lots of cores. i dont know. may be i missed out on some concepts. please educate me. here is the excel file https://docs.google.com/spreadsheets/d/1a1Fb1...mp;rtpof=true&sd=true oh, this is Covid19 wu and GPU was computing in other project(milkyway@home). the CPU is AMD 3900x with 12/24 cores/thrd btw thank you [Edit 2 times, last edit by kcharuso at Nov 21, 2021 7:30:59 AM] |
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smoke1943
Cruncher US Joined: Dec 24, 2021 Post Count: 6 Status: Offline Project Badges: 
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hi all, i was wondering the differences in results an overclock and various cpu core count would make so i collected a few data and the result is in an excel. i hope my calculations are correct but it did not make much sense to me. it seems like using less cores to compute finish more wu. if so, there is no need to rely on expensive CPU with lots of cores. i dont know. may be i missed out on some concepts. please educate me. here is the excel file https://docs.google.com/spreadsheets/d/1a1Fb1...mp;rtpof=true&sd=true oh, this is Covid19 wu and GPU was computing in other project(milkyway@home). the CPU is AMD 3900x with 12/24 cores/thrd btw thank you I think it makes sense that a CPU would be faster if not split |
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Mike.Gibson
Ace Cruncher England Joined: Aug 23, 2007 Post Count: 12120 Status: Offline Project Badges: 
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This should be in the hardware chat room. However, the usual consensus is that using more cores/threads increases the time spent on each unit, but the total output does increase - just not in proportion to the number of cores/threads.
Whether there is more output per unit of electricity is debatable. Mike |
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Sgt.Joe
Ace Cruncher USA Joined: Jul 4, 2006 Post Count: 7545 Status: Offline Project Badges: 
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If you are running your CPU at 100% it should run at a fairly constant rate (ignoring turbo mode). However there are other constraints on the system as a whole which will have an effect on the length of time it takes to finish any one work unit. Latency in the communication channels in getting information into and out of the CPU is one of these. Any delays in the information transfer will slow down the entire process. The amounts of cache will also have an effect on the availability of the system to feed the CPU. Any cache misses will slow down progress. Cache misses are more likely with smaller cache sizes. Another factor is the overhead imposed by the operating system. The more the operating system uses the CPU, the less of the CPU is available to deal with the work unit.
----------------------------------------Using hyperthreading is a different story than just the speed of the CPU. The idea behind hyperthreading is to let each CPU core work on two workunits at the same time, utilizing the gaps in the information feed. One core running one work unit at a time will finish a work unit faster than the core running two work units in hyperthreading mode. However, in hyperthreading mode there will be somewhere between 50% and 70% more work units processed. This will vary among different projects and different systems. Cheers
Sgt. Joe
*Minnesota Crunchers* |
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