In my last post – Bitcoin Mining for Fun and (not much) Profit – I described my experiences with mining for Bitcoins using my (3) Radeon HD 7970 graphics cards. I ceased my GPU-based mining operations because even with my max mining rate with the three cards of ~ 1.5GH/s I am only able to mine about 0.001BTC/day. Even at a valuation of $1000/BTC (current best-case-scenario) that only comes to about $1/day if I ran them all full-speed with fans-a-blazing. Definitely not worth the power they’d draw, much less tying up two machines 24×7.
I have now switched my efforts over from mining Bitcoins to mining a similar virtual currency (arguably the next contender for the Bitcoin virtual currency top-spot) called a Litecoin. Mining Litecoins is very similar to mining for Bitcoins. I even use the same CGMiner software (version 3.7.2 as it’s the last version that supports GPU mining afaik) except I have to throw in the “-scrypt” parameter into the command-line when I fire up the software. I also have to point it at a Litecoin mining pool & port as well.
The process is very similar to Bitcoin mining. You have a virtual wallet – I am running the Litecoin-Qt version that they link to from the main Litecoin site. You still mine for the Litecoins using software such as CGMiner or the like using your GPUs. The main difference between Litecoin and Bitcoin is that the hashing algorithm that you’re running is using Scrypt, which is a password-based key derivation function that is both computationally intensive, but also requires a healthy chunk of memory for each iteration (~128KB/iteration I believe). This makes Litecoin mining much more difficult to parallelize using custom Application Specific Integrated Circuits (ASICs) or Field Programmable Gate Arrays (FPGAs) – which are in heavy use for Bitcoin mining now. This means that my GPUs which, since I am running the mining software on a PC with access to lots of RAM, gain new life as Litecoin mining rigs.
Remember when I said that I could get ~600MH/s from the Radeon HD 7970 graphics cards (each) when mining for Bitcoins? The same 7970s are only able to calculate ~ 580KH/s (that’s kilo – meaning thousand hashes per second) for a total of ~1.5MH/s with all (3) cards running straight out. Since there aren’t any ASICs (that I’m aware of at this time) to put them to shame (not yet anyways, more on that later) – that means that GPUs are pretty much the shizzle for Litecoin mining at the moment.
To give you some perspective, I’ve been tasking all (3) of my 7970’s to Litecoin mining on a Litecoin P2Pool mining pool node for the past week or so. In that time I’ve been able to acquire about 3.8LTC. At a market valuation (as of today) of $24.1/LTC, that’s 3.8LTC x ($24.1/LTC) or $91.58 worth of Litecoins that I was able to mine with them in a week. If I tasked them to Bitcoin mining I’d make about $7 worth of Bitcoins based on my back of the napkin calculations. So, for now, it’s much more profitable to mine Litecoins with them.
I haven’t given up on the Bitcoin mining. I’m just not mining using GPUs – I’m using (2) Butterfly Labs ASIC mining appliances to do that now. One is capable of performing 30GH/s and the second can perform 10GH/s for a total of ~40GH/s. As of today, they are able to generate about 0.014BTC/day at today’s difficulties or (assuming a best case $1000/BTC valuation) about $14/day or $98/week. Not too far off from the Litecoin operation using the GPUs.
This GPU re-tasking may be short-lived however. I ran across a company called Alpha Technology which claims to be coming out with a “Viper (Scrypt) ASIC Miner” which, according to their website, are capable of doing 5MH/s & 25MH/s depending on the unit. As with all good arms races, it seems that my GPUs may soon be relegated to strictly gaming it seems.
I posted my Bitcoin and Litecoin QR codes and addresses off to the right side of the blog now BTW. Just in case anybody is sitting on a butt-load of virtual currency and would like to help fund my virtual currency mining “habit” ;?)