I've come to realize that trying to model future income for scrypt miners is not easy. Let's start by using Litecoin as a base--it is really not much use to attempt to consider all of the alts out there (rather, you can use 110% of LTC profitability or something if you are on a good multipool).

Take a look at the difficulty chart for litecoin over the last month)



Prior to that, it was fairly exponential:



For now, at least, it is flat to declining (probably the last of the GPUs are being taken offline, and not being replaced by ASICs as profitability is in question and hence demand is not quite there).

Next, we need to look at the LTC price (we can consider LTC/USD prices). In 2014, LTC has trended steadily down from .03 to about .01 BTC currently. Expressed in USD, it has trended down from about $25 to about $5. This is a 75% loss for the year. Over that same time, difficulty went up about 12 times. But that trend appears to have flattened out.

Profitability ($/MH) at the beginning of the year for litecoin went from $10/MH/day (ah, the good ol' days) to a current $0.187/MH/day. That looks gloomy, as mining is only 1.87% as profitability as in January.

However, current scrypt miners hash at about 25W/Mh (e.g. Zeusminer Lightning X6, 40MH@1000W), which at $0.12/Kwh means about $0.07/MH/day.

So, there's still some wiggle room for profitability, but it's very difficult to predict from here. I think difficulty should respond to price changes from here, which would essentially imply that for the time being, the profitability equation might not change much.

I would encourage discussion on this topic, since I can't really come up with any way to predict scrypt mining profitability going forward.

Thinking of selling this heli as I have not flown it in awhile. Have basically switched to a 550-size (which I have not flown in awhile either LOL). This is a ThunderTiger Raptor e620 with full CNC aluminum Kasama head and tail, Futaba BLS-451 brushless servos, Scorpion motor, Phoenix ESC, GY611 gyro, carbon fiber Curtis Youngblood 600 main blades & tail rotor blades. This is a big, easy-flying heli. Would be available for questions from buyer after the sale.

Requires 2x5s5000 batteries (not included) and radio (though I could include a 2.4 GHz Futaba receiver).

Any interest?

Difficulty jumped to 15.6 million from 12.1 million, a 28% increase. Welcome to ASIC world...be very careful with your hardware investments!

[at least]

Here are my assumptions to arrive at this conclusion:

• Alt coins are basically "dead," or at best, give a quick bonus for mining early, then quickly go down to 100% or less of BTC.
• Difficulty will continue to increase by at least 10% every two weeks for at least 7 months. We've been averaging 17% every two weeks, and we have not even seen the biggest ASIC surges yet.
• Bitcoin price may rise, but it may not. Assuming a miner cashes BTC immediately, later rises in BTC mean very little additional income. If you expect BTC to rise much later, just buy BTC now.
• Assume 2.5 "real-world" MH/J efficiency--that is about the best I've seen.
• Assume a base of $116/BTC
• Assume $0.11/KWh.

If these assumptions are correct (and I think they're essentially best-case), you can expect to make 3.4 BTC per GH of hashing power over the economic life of the card (which is about 237 days at the moment). To my knowledge, this means that there are ZERO economic GPUs out there right now.

Let's take a 7970 at 200 watts and 650 MH/s (which is a generous 3+ MH/J):
Total BTC earned after electricity: 2.53 ($293.77)
Time to 0 BTC/day: 280 days

In short, DO NOT buy a card just to mine.