OK...sorry if this has been asked a billion times before but what actually is the credit. My PC processes one and claims 20.31 credits and taking 11,827.36 seconds to do. Another users PC claims 38.10 credits and takes 11,636.80 seconds to do. how come there is so much difference in the claimed credit? Between these two results there is a difference of 3-4 mins. How does the whole credit thing actually work?!?!?!

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<img src="http://www.boincsynergy.com/images/stats/comb-1093.jpg">
<br>BOINC-ing since 23rd March 2005.

OK...sorry if this has been asked a billion times before but what actually is the credit. My PC processes one and claims 20.31 credits and taking 11,827.36 seconds to do. Another users PC claims 38.10 credits and takes 11,636.80 seconds to do. how come there is so much difference in the claimed credit? Between these two results there is a difference of 3-4 mins. How does the whole credit thing actually work?!?!?!

There is a full discussion of credits in the BOINC Wiki, but generally it is a measure of how much computing power was used to crunch the unit.

A faster processor will claim more credit for the same length of time than a slower processor would. When enough results are returned to validate a work unit, the highest and lowest claimed credit are thrown out and the rest averaged to determine the granted credit. All of the computers that sent in results are given the same granted credit.

This is complicated a bit by what are called optimized clients. These SETI@home clients are tweaked and streamlined to process faster. They tend to claim less credit that they "should" and are usually the lowest claim that gets thrown out. (There are complicated technical means of correcting for this, but that is a topic for another day.)

In theory, different computers (optimized clients notwithstanding) should claim virtually the same number of credits for the same work unit. In reality, they don't, which is why the granted credit system is in place for fairness.

(Edited for spelling)

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No animals were harmed in the making of the above post... much.