Bitcoin Forum

Bitcoin => Mining => Topic started by: pletharoe on October 19, 2013, 02:58:42 PM



Title: Why does my hash rate vary?
Post by: pletharoe on October 19, 2013, 02:58:42 PM
I'm using a KnC Jupiter, although this question should apply to any machine which is only used for mining.

Chip clock speeds are constant.  If there is unlimited access to work (I believe this is the case with most pools), why does the miner's hash rate vary with time?


Title: Re: Why does my hash rate vary?
Post by: Flashman on October 19, 2013, 03:12:55 PM
Because it's all an average.

Say it's all potatoes, you can peel 4 potatoes a minute on average. But, sometimes you get small smooth ones that take only 7 or 8 seconds, sometimes you get big knobbly ones with lots of eyes that take 30 seconds plus. So you reach into the bag and get another tater and start peeling, sometimes you get lucky and get 10 small smooth ones in a row and your "rate" looks great, but then you have a run of big knobbly ones and you slow down again.


Title: Re: Why does my hash rate vary?
Post by: pletharoe on October 19, 2013, 03:29:10 PM
Thanks for the spud analogy!  I hadn't realised that some hashes are harder to calculate than others.


Title: Re: Why does my hash rate vary?
Post by: MTBmanTT on October 19, 2013, 08:27:22 PM
Because it's all an average.

Say it's all potatoes, you can peel 4 potatoes a minute on average. But, sometimes you get small smooth ones that take only 7 or 8 seconds, sometimes you get big knobbly ones with lots of eyes that take 30 seconds plus. So you reach into the bag and get another tater and start peeling, sometimes you get lucky and get 10 small smooth ones in a row and your "rate" looks great, but then you have a run of big knobbly ones and you slow down again.

Thats a pretty good analogy, I like that.


Title: Re: Why does my hash rate vary?
Post by: madcratebuilder on October 20, 2013, 05:52:20 PM
Damn, I want some French fries, good analogy.


Title: Re: Why does my hash rate vary?
Post by: eleuthria on October 20, 2013, 08:55:22 PM
Thanks for the spud analogy!  I hadn't realised that some hashes are harder to calculate than others.

Technically all hashes are the same difficulty to calculate/time to generate.  The difference is, each one is a completely separate 256 bit output, and a 'share' is only a certain subset of them.  The traditional difficulty 1 share is approximately a 1 in 4.2 billion chance (or 4.2 Gigahashes).  So if you do 4.2 GH/s, you will on average get one per second.  Then it falls into the analogy above :).


Title: Re: Why does my hash rate vary?
Post by: overunity on October 21, 2013, 06:23:54 AM
On my Usb sticks at Bitminter I noticed that a stale proof of work sends my hashrate to near zero .possibly cause of the tata effect hehe. :o


Title: Re: Why does my hash rate vary?
Post by: leannemckim46 on October 21, 2013, 10:55:12 AM
Some time u get lots of french fries and sometimes less :)