At stock speed you're looking at ~300MH/s. At core voltage, o/c to 925~950 is expectable on any given card. On my card, 925 is 350MH/s, 940 is 360MH/s, I haven't seen how far it can go yet. This is all with ram at 300MHz, -f1 and -w256 on win7

Take a look at this graph.  It shows difficulty versus time on a logarithmic scale.  (There's also a linear scale version available here.)  You can see that difficulty has increased from roughly 200 to 80000 (i.e. by a factor of 400) since the middle of July 2010.  That's 9 months, or 39 weeks.  Difficulty adjusts every two weeks, so that is 19 adjustment periods.  That means an average of roughly a 37% increase in difficulty every two weeks over this time period, since 1.37¹⁹ ~= 400.

You can work this into your equations easily.  You start with the equation:

factor(rate, numPeriods) = (1 + rate - (1 + rate)^-numPeriods) / rate

In PHP, that would be:


You need to allow the user to enter in a rate, which is how much they expect the difficulty to increase per two week period.  You could default this to 0.37 for example, or to a more conservative value like 0.20 if you think the number of people mining bitcoins isn't going to keep increasing at the historical rate.

For your specific code, you'd change it to be something like this:


As an example, your current page with the default values shows 2676.80 coins per year (you say blocks, but mean coins). That's 103 per two week period.  We then calculate "factor" as above, assuming a rate of 0.20:


For a final answer of 613.88, rather than 2676.80.  This is a huge difference, but is very real.  If you use a rate of 0.37, you get a factor of 3.70, for a final answer of 381.1 coins, which is seven times less.

I would also suggest that you allow people to enter the number of periods, rather than one year.

Please try this & give confirmed confirmations.

The MAXIMUM STABLE CONSTANT hash/s is obtained by a formula which i tried & found out. Instead of varying hash/s, it gives some what constant hash/s
Memory clock = (core clock /3) + 14
Please try, test & confirm with your results & please put your data here with your Graphics card & hash/s you get (you can add OS, 32 or 64, catalyst version & stream or APP version also).

Donations & loans are always welcome.
Thanks.

Ha, I did the same thing but with different assumptions, I even measured the actual Wattage being used on the machine with a kill-a-watt meter.  Here is what I came up with (tl;dr = 3.5 months to recoup hardware if the difficulty doesn't change).

Note: all of the hardware was extra gear I had and/or snagged for a bargain locally, usually used via Craigslist so my hardware cost is low vs. retail.

I could send the spreadsheet to anyone interested.

I would have to agree.

Which computer was running 100mh/s slower? deepbit or slush's?

+1

I saw the new addition paypal mining. its a really brilliant idea.
But how you calculate the btc value to paypal value?
Which exchange you will use & also you use fixed rate or daily or hourly rate?
Also BTC/PPUSD changes even hourly, so, if a user waits for the maximum BTC rate , then he set use instant payout?
or you pay daily at a particular time UTC 0:00 as you used to pay before & you take the value of BTC at that point & convert or You convert the lowest value on that day?....

It would be better if you explain and also add a FAQ in the site itself.

Thanks for adding paypal option, it makes miners not to wait for his/her bitcoins to sell in mtgox or otc or black market.