Profit and Loss

Looking at my Gridseeds and wondering if I should mod the hardware, and if so by how much, it seemed to me that the alarming increase in power usage as clock speed increases might have undesirable effects on the profitability. So I decided to get out my calculator. The results below are based on some tests performed by myself on the latest version of the Gridseed 5 chip module (the one with surface mount LED's). I modified one by changing R52 to 39k and another by changing R52 to 47K. The modules all had the 5V fan mod and were clocked at 850MHz, 1000MHz and 1200MHz, these values were chosen as the maximum which gave zero (or close to it) errors. The power cost is calculated from what I pay at about $0.20/KWHour and the modules using 4W, 15W and 25W. All figures relate to one Gridseed module running for one day and based on a bitcoin value of $460. Earnings figures are based upon a return of 0.004386 BTC/MHash/day.

R52	Power Cost	Earns Today	Profit Today	Earns Month 2	Profit Month 2	Earns Month 3	Profit Month 3
33k(standard)	$0.019	$0.72	$0.701	$0.36	$0.341	$0.18	$0.161
39k	$0.072	$0.857	$0.785	$0.4285	$0.3565	$0.21425	$0.14225
47k	$0.12	$1.029	$0.909	$0.5145	$0.3945	$0.25725	$0.13725

So assuming that the income from mining halves each month (seems likely it will) we can see that in just 2 or 3 months time it will be best to have unmodified Gridseeds.
I must emphasise that these figures are far from definitive and should only be viewed as a rough estimate. Your modules might give different results and your power cost is probably different from mine.
Overall I think my best bet is to leave mine standard with no fans at all rather than go to all the trouble of modding them only to have to put them back in a month or two.