Can anyone explain this?
7 Feb 2011 10:57:25 UTC
Topic 195634
(moderation:
There appears to be a problem with the BOINC calibration of the processor.
I have two machines. In both cases the integer and float are per core. I get them from the standard out file. I got the RAC from allprojects.com.
Phenom 1.8 GHz, 8221 int, 1357 float, 1666 RAC
Athlon 2.6 GHz, 3759 int, 612 float, 2367 RAC
The ratio of the clocks is 1.44. The ratio of the RAC is 1.42. The ratio of both integer and float is more than double in favor of the slower machine.
So the speed at which a WU is processed depends upon the clock speed rather than the rate at which numbers are crunched? The BOINC calibration means something other than the usual or something that loves and L3 cache? I admit to being surprised with the results on the slower Phenom machine compared to the Athlon.
These are plain vanilla machines from HP. Both have the same MOBO graphics chipset and neither has a "gamer's" video card. Both run essentially the same linux kernel differing only be Redhat 12 on the slower and 13 on the faster.
Any suggestions?
Can anyone explain this?
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There are a couple of factors that affect the reported CPU speed quite a lot.
System load at the moment of testing. If system performs some other non-niced tasks when BOINC does benchmarks, indicated CPU speed can be quite lower than the one reported when computer is otherwise idle.
Exact breed of BOINC core client. If you're running not-exactly-same executable on both machines, then calibration loops of both BOINC executables could be quite differently optimized. A while ago there was a movement to optimize the very same calibration loops in order to get client report more OPs to be done in real science application.
Amount of CPU cache: calibration loops run nicely if they fit entirely into CPU cache ... thus slower CPU with larger cache can produce better results. That's not normally the case with science application.
All in all this number is nowadays not used much and should be omitted.
Metod ...
RE: There are a couple of
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I chose to give a relevant summary in my post. I have checked several calibrations and they agree to less than 1%.