GPU Mining - still profitable under certain conditions?

[martynw2000]

I have a fairly small setup planned made out of spare parts essentially. - 4 computers each with 7970's, giving a combined hashrate of approx. 2.7Gh/s. The computers and cards are already paid for and don't owe me anything, and they are all located somewhere where I don't have to pay for the energy usage. Under these conditions (i.e. no overheads), I think GPU mining is still okay for now, correct?

I know I'm not going to be making as much as the big boys out there - but it's not much problem for me to keep these machines churning away 24/7.

I'm not so clever at the math in all this - but am I right in thinking that if the difficulty rate increases at roughly the same rate as the exchange rate, then nothing much changes? (eg. if difficulty doubles, it takes twice as long to get a bitcoin, but it's worth twice as much, so net gain/loss = 0). Or am I missing something.

Sorry if this is too basic, but I'm guessing this is what the newbie section is for.

TIA

[Aahzman]

"GUI"

I do not think you know what this acronym means, my friend.

For 2.7Gh/s, zero energy costs and zero depreciation of hardware, go for it. leave em grinding away until ASICs blow the difficulty to the moon and beyond.

[Ortulas]

Well tomorrow's a different day, who knows what's going to happen with prices. Everything depends on what happens with the value of the currency and the difficulty of the network.

[martynw2000]

"GUI"

I do not think you know what this acronym means, my friend.

LOL - yes, sorry, you're quite right. Got my anronyms mixed up. Quite easy for an old-timer like me. Anyway, I fixed it.

Oh, and I do know that GUI stands for Graphical User Interface btw - but what I really meant was GPU as in Graphics Processing Unit. My bad.

Or... GUI could mean the Golfing Union of Ireland of course!

[marketermac]

Your math sounds correct with one exception...doubling of difficulty rate doesn't mean doubling of BTC price...and vice versa.

It's only worth what someone is willing to pay for it, and on the next update the difficulty could quadruple and people could be paying half the USD (or whatever currency for that matter) for a single BTC. Nobody knows what tomorrow will bring.

Have to agree though about mining for you, if you don't mind keeping the 7970s instead of selling them, then by all means mine away with your free electric.