Topic: Litecoin mining with dual 6950 setup (Read 1433 times)

You, sir, are my hero. I luckily am good with linux. That saves me 100 dollars and yeah I would need 64 bit or the computer wouldn't even be able to address the entirety of the memory of the cards themselves. I'm probably not gonna get a DVD drive. I'll just use a thumb drive to install it to a hard drive (which I luckily have). And thank you for the calculator. I haven't been able to find one that takes into account for electricity so I have been using bitcoin ones to get a rough idea. I'm betting LTC will rise otherwise I wouldn't want to invest in a system for it.

Thanks again for all your help. I seriously feel a lot better going into this now with more knowledge.

well, for hashing alone, and @ 360 for both, not a bad deal.
Though 1000 khash is most likely not going to happen, anyone getting higher than ~450 even overclocked to hell and back, has an earlier GPU that was unlockabale for more shaders (look up 6950 to 6970 mod). Most newer 6950s will not unlock, so bet on getting 440-450 each with good overclock and tweaking.

Just dont blow lots on the mb and memory, but get a good power supply.

No real way to not have to upgrade the supply later for more cards if money is that tight now, but shop for a good deal on a good rated one, 600 watts should be more than adequate and cheap as well, 500-550w might cut it if its a good one. My whole system uses 250w, but I am also using it for other things @ same time..

Should get a motherboard with 3-4 PCI Express slots for future expansion, that way you can just throw the next two in without removing the others (provided that they are not horribly bad power/coin ratio by then). You can find pretty cheap decent ones with 1 x16 and 2-3 x1 slots (1x has no loss for hashing duty, but you will need to use a riser because the x16 card wont fit in the x1 slot). What CPU socket it has is irrelevant (so long as its not so outdated that its hard/expensive to find a CPU for it), shop for the features you need: lots of PCI Express, a wired network adapter on board, preferably 4 slots for ram for future upgrade.

Due to the risers, you wont be able to use a standard case, but you shouldn't be wasting money on one of those anyways. See tacotime's milk-crate (or some other similar plastic crate) build on these forums for ideas: Nice, simple, cheap, and most importantly, LOTS of airflow.

It is generally advised for LTC mining to have as many GB RAM as the total of the GPU memory, so 2+2 = 4, but should have a couple for the system. Whether it is running in double data rate is also more or less irrelevant, so don't worry about buying in pairs. If 3, 2GB sticks are cheaper than 2, 4GB ones, go cheaper, can get more RAM cheap later (so long as the selected motherboard has 4 slots of course). Just stick with stuff with at least halfway decent ratings, read the reviews, a lot of times the ratings are low just because it bills itself as enthusiast RAM, but cant overclock well. Overclocked RAM is irrelevant to your needs, so occasionally good sales can be had this way.

No need to worry about core count, or speed of the CPU, just go with the cheapest one that fits the socket of the chosen Motherboard.

If you are even half familiar with Linux, don't worry about buying a copy of windows. If you absolutely MUST purchase windows, stick with 7, and check the forums a bit, but I am pretty sure 64 bit is the way to go.

And so long as you have a spare cd drive that you can borrow from your computer or a friend's, don't buy that either, you will likely only need it once. Make sure that it is the same as the motherboard supports, some boards don't have IDE anymore, only SATA, so be aware. Otherwise, cheapest dvd reader you can get.


NOW, after figuring out all that, and selecting parts (or scrounging if you know someone with spares, in which case, don't really worry about it having more PCI Express slots than 2, free is better than cheap any day of the week), add up the total cost.
Now get familiar with a LTC mining profit calculator, I recommend Burnside's LTC miner calc, as it takes power into account. Play with it, betting on 880 kHash/sec and 500-600 watts to be safe, considering the loss to voltage transformation. Figure your profit/loss, take into account that the difficulty will rise (get familiar with difficulty charts for LTC to see what I mean), and that the price per coin is a variable (though I believe it is safe to assume an overall rise in the long term).
Take some shots at investment recovery time, and finally, decide if its worth it.

The price for the capability of the cards is good.

I wish you happy hashing,

Sincerely,
SamuelSG

The only problem I have with 7950's is that I don't have the cash to pay for 2 right now. My cash is restricted and for around $360 I can get 2 6950's shipped. Those will get me somewhere between 800-1000 khash/s depending on if I overclock them. I know it's not great for an upgrade path but it would basically be something to hold me over until next year to get some hd 8000 series cards whenever they come out. This would be a mining only rig I don't play enough games on a computer to justify that much firepower for it. (My laptop has an Nvidia gt 650m. Pretty midrange and it runs everything I want fine)

You are quite right. However, it will be quite some time yet till FPGA's or ASIC's are designed for litecoin.
And with careful consideration of all costs, and of course faith that the price doesn't stay as low  , it is still possible to enter, though the margins are slim.

And it is still a sure bet that, if you are a gamer, graphical artist, or video editor (insert other gpu-compute heavy task here if you can think of it), you will be able to significantly subsidize the investment in hardware awesomely advantageous in those fields.
A good friend of mine has very nearly paid off his 3x7970 3d Design and Animation (and of course some gaming) rig by mining in the 16 hours a day he is not working. He did start early though. He is the one who got me interested in it, late to the game as it is.

I think it's just a matter of time before GPU mining is dead, with ASIC products pushing multiple GH/s and FPGA pushing near 1GH/s I think the end is near to be able to financially motivate a GPU rig.

I get ~444 kHash/sec mining litecoin with my single 6950 with very little overclock and almost no tweaking necessary.

You could double that as a basic assumption of what you will get.

I would say go for it IF you are buying it for gaming, and will mine as a hobby (or to pay the electricity, internet and game costs) without the expectation of making a lot more than that. I would maybe advise looking into newer cards just because they game better.
7870GHz editions will give just under mining (at ~400-425 kHash/sec), but better gaming experience for $230-250 each.
and the 7950s will blow them away both mining (at ~600= kHash/sec), and gaming for ~$300 each, and can be overclocked to perform near 7970 levels with out much effort in a good case.

couldnt find much price data on 6950s anymore, as they are outdated, but I would say unless you find a really good deal on them, go for the 7870s no questions asked. The 7000 series crossfires so much smoother, and you will never regret the decision.

If, however, you are building to mine with alone, and understand where you can shave costs on the parts and where you cant...
Then get a motherboard with at least 3 PCI Express slots (it doesn't matter if they are all x16, x1 works just fine for mining) if not 4 or 5, which can be had for a reasonable price. And start with 2 7950s, thus having an easy expansion path for if you find the money compelling.

The only difference is for Litecoin you also need a decent amount of ram. Your 6950's have 2gb of dedicated memory each so you would want at least 4 gb of system ram plus another 1 or 2 to run the Operating system.

Would this be at all viable/smart? I haven't purchased anything yet but would like advice on it. If it is in any way smart what other hardware would be needed? Mostly I need help in the mobo and PSU arena. The rest is pretty easy to put together.