Miner Variance

[optimator]

How do you calculate the possible hashing variance of a miner?

Say to have an Avalon that's rated at 66 GH/s. You are on a pool giving you diff 64 shares.

What would be the minimum and maximum hash rates you'd expect to see?

[DrG]

Has rates won't vary on your end (other than +/- 2-3 MH/s)

Your submitted shares per minute will vary.  In CGMiner that's the "U" that's in the top right.  About 1 share per minute for every 71 MH/s, so a 600MH/s miner would average about 8.5 shares/minute.

That's the expected average.  Sometimes you'll submit 2 shares per minute, sometimes you'll submit 15.  That's why what the pool shows your hashrate to be will vary - it has to guess based on your submitted share count.  This won't show much variance after about an hour.

Does that answer your question?

[optimator]

Has rates won't vary on your end (other than +/- 2-3 MH/s)

Your submitted shares per minute will vary.  In CGMiner that's the "U" that's in the top right.  About 1 share per minute for every 71 MH/s, so a 600MH/s miner would average about 8.5 shares/minute.

That's the expected average.  Sometimes you'll submit 2 shares per minute, sometimes you'll submit 15.  That's why what the pool shows your hashrate to be will vary - it has to guess based on your submitted share count.  This won't show much variance after about an hour.

Does that answer your question?

Let me try my question again  

If you are solo mining the probability of finding a block is constant, but there is variance for when you will find the block. In a pool with Diff 1 shares the variance is almost eliminated.

My thinking is that with Diff64 shares there is a noticeable difference in variance (that is, when the diff64 share is reported to the pool). That variance will be reflected in the pool's reported hash rate (since pools calculate the hash rate based on submitted work).

For example, the Avalon is rated at 66,000 MH/s, but the pool reports between 63,000 MH/s and 71,000 MH/s.

My question is how can I calculated the anticipated pool reported hash rate?

There was a post, that I now can't find, that describe the effect variance had on pool dollar reserve requirements for PPS. That post had the math I think I need to calculate the anticipated pool hash rate for a give hash rate and share difficulty.

EDIT: here's the link to the paper I mentioned - http://arxiv.org/pdf/1112.4980.pdf

[organofcorti]

I'll have a bit more time to answer questions later on, but until then have  a read of this:

http://organofcorti.blogspot.com/2012/10/71-variable-pool-difficulty.html

It also explains why you see miner variance, and links to a look up table confidence intervals for hashrates.

[....]
EDIT: here's the link to the paper I mentioned - http://arxiv.org/pdf/1112.4980.pdf

There's a newer version of Meni's paper at https://bitcoil.co.il/pool_analysis.pdf

[optimator]