Altcurrency Mining Question

[cryptopi]

I have never GPU mined a currency before. I recently decided that I would like to get involved in mining (via a dedicated GPU mining rig). I also decided that my rig will probably generate 3-6 Mhashes for scrypt with 4-8 7970s (is that right?).

I would like to assemble a spreadsheet in order to see if the costs are worth it. My plan is to mine LTC in spare time and then mine new/popular coins as they come out or as they gain value. My questions are twofold:

• is it, in your opinion, worth it to build a rig right now?
• for any given coin at any given difficulty, is there any way to calculate how much of that coin I will mine at a certain hashrate (on average) without the use of a premade online calculator (because the new coins do not have such premade calculators)?

Thanks, any insight at all would be appreciated

[Eli0t]

you can use the calculator at coinwarz to put in hash, difficulty, reward and current price. the coin specific links are only to put in the parameters for that coin

http://www.coinwarz.com/calculators/litecoin-mining-calculator

[Loktera]

Hard to say if it's worth it. Right now the return on investment is quite long, which is only really going to be changed by a sharp increase in the value of a coin. You must then ask yourself: would it have been more worth it to just invest the same money in the coin in the first place?

I'd advise against 7970s if you do decide to mine, however. 7950s offer much better hash rates for the cost/power draw.