Bitcoin Forum

Gui miner is telling me that I am getting 256 Mhash/s and then I look on the statistics page at deepbit where I am pool mining and it says that I am averaging 200 Mhash/s.  What is the deal with the sizable difference between the two?

GuiMiner say right; all mining pool a little wrong

Thank you, I appreciate it.  Now does this mean that my returns and rewards are going to be 'a little off' or will they remain accurate?

I have never seen the Mhash/sec accurate on any pool website yet.
But the payments should be perfect, they are based on all your returned shares. 50*(yourshares/totalshares)

They don't actually know how many hashes you are calculating.  there just guessing based on blocks submited/time.

There are several reasons this could be:

1) You are just unlucky. You are doing 256Mh/s but have only generated the amount of shares expected for 200Mh/s. This is all the pool can go by.

2) The pool is measuring inaccurately. Pools are famous for getting this calculation wrong. For one thing, it might include averaging over a period of time when you weren't mining.

3) You are overclocked or otherwise bugged in some way, so while you are doing 256Mh/s, only about 200Mh/s of them are correct, and so you aren't generating as many shares as you should.

One way to figure this out is to track how many shares you generate in a particular period of time (the longer the better) and how many shares were accepted by the pool in that same time period. If you are generating too few shares or more than a tiny fraction of your shares are being rejected, that points to a problem on your end.

Okay so for instance I have 2528 shares accepted and 11 stale/invalid.  Is that a reasonable ratio for shares accepted versus rejected? I am overclocked, is there anything other visible way to tell if it is generating errors?

That's only 0.44% stale shares.... it's great!

just use another pool. deepbit charges a big fee anyway.

On deepbit you can set "Averaging window for hashrate display" to 60 minutes, this way the variance of the Mhash/s display will be reduced. I'm pretty near at what GUIMiner says (variance smaller than 5%).

Pools just use an algorithm to guess your hash speed based on the amount of submitted shares.

Add a little variance (as is normal), and you get obscure estimated hash speeds.

What pool do you suggest I use that has a small fee?

My advise would be to skip the largest two, to avoid potential issues (https://en.bitcoin.it/wiki/Weaknesses#Attacker_has_a_lot_of_computing_power) that could cause bitcoins to devalue, and pick anyone you like the look of https://en.bitcoin.it/wiki/Comparison_of_mining_pools

+1 for rfcpool.com  :)

NoFeeMining has no fees and is hosted in usa