Topic: Help build a 3 x 7950 mining rig? (Read 4104 times)

I see no problems with him parting together a gaming computer and then mining as well.
 
I have two 7970s that are barely (together) making 0.1 btc every other day, but it's my primary gaming computer.  Before I discovered bitcoins a couple years ago I was "wasting" electricity for SETI@home and distributed.net, and those weren't giving me any money in return.  I view the hardware cost at *zero* because it's a cost I would have spent anyway for gaming.  I'm not doing this to make money.  Sure it's nice getting money back, but it's not my primary objective.
 
So before y'all go bashing people for wanting to mine with GPU, consider the alternatives.  My machine is always on 24/7, and if I wasn't doing BTC I'd be doing other shit for free.
 
Also, I don't know his electricity, but here in Kansas I only pay $0.04 per kWh.  So it costs me less than a dollar a day to mine. 
 
Even if I can only mine one BTC a month, or every other month, or shit even one a year, I will keep mining with my GPUs

i bought a powercolor 7870 myst edition?   for $208.   its getting 506 mh/s   -8% voltage, fan @ 100%,  73deg celcius,    ram at 150mhz, gpu at 1205mhz.
using guiminer:  -v -w 256   (my flags used).
I think I can push it to 550-600mh/s   been running 14 days straight so far.


I question if I should get another 7870 or a 7950 since I am getting good efficiency from my $208 7870.
GPU mining is profitable even right now.  You can mine, trade and day trade your btc / usd.

All good points AlphaWolf. I willingly admit that ASIC's are better return dollar for dollar. But until they're available en mass, GPU's mining is going to be profitable for the simple reason tho they make up less of a hashrate, they make up a majority of devices that a miner can obtain at the moment. That may change anywhere invetween two six months... we don't know. Also take into account what the cost of electricity is, (higher $ per KWH areas have more of an incentive to move to ASICs than lower $ per KWH areas,) and if you can get GPU's cheap enough to pay themselves off before the difficulty ramps up.

Honestly it comes down to this...

If you expect BTC price to ramp up again and asics to have more delays then Buy GPU's with cash and mine.

If you expect BTC price and Difficulty to Ramp up, Buy BTC and hold.

If you expect BTC price to fall Difficulty to ramp up, Buy ASIC's



Note: I have orders with BFL and AVALON (batch 3), and I'm still buying 7950/7970's to add to my farm.

First, the OP has made it clear that he's going to us the GPU's for gaming... so the rest of this post is directed at those who are thinking about buying GPUs for investment...


Yeah, the people who backed their advice up with numbers are the liars, but your claim backed by "hey listen to me!" is probably golden...

Sure GPU mining is more profitable than it's ever been... assuming you already own the cards AND only because of a bubble.  But the fact of the matter is that Avalon is shipping ASICs, BFL has shipped a small batch and will theoretically be shipping many more soon, and many other ASIC operations are due to come online in less time than 3 months.  I showed how in 3 months, the OP would still be very much in the hole even assuming the price of BTC doesn't drop.  Unless the price of BTC increases *substantially*, you will lose money just running your GPUs once all those ASICs come online. 


Let's break down each of the claims by each of the authors:

First claim: "Build your GPU rigs with the price of btc @ it's all time high, since at a future date, it WILL pass that."

Counter Claim:  If the price of BTC is guaranteed to go up as you say, it makes more sense to spend the equivalent amount of money on an ASIC miner, which will produce far more BTC for far less electricity cost, which allows it to stay ahead of the difficulty/profitability curve.  The price will have to go up at a rate higher than people are adding hashpower to the network for a GPU to work out.  Even the small ASIC miners will replace the hashpower of 8 7950s, and only costs as much as ONE.  And while those 8 7950's will use 1600 Watts, the ASIC miner that replaces them will only use 30.  If your purpose is solely as an investment, why would you pick the option that costs more to purchase, gives 1/8 the return and costs 53x more to run?  Anyone?  Bueller....  Bueller...

Judgement:  I think the numbers speak for themselves.  If this is an investment it's downright foolish to buy GPUs.

Second claim: "I mean even if difficulty goes up, it is possible that BTC/LTC will continue to rise so there ROI will still be there. "

Counter Claims: 1: Difficulty is guaranteed to go up.  2:  It is equally possible that BTC/LTC will fall, so your ROI would be even worse.
Judgement:  At best a tie.  Nobody knows what the price of BTC/LTC will do.  We DO know with ASICs coming online that difficulty will increase quickly, which will make GPUs increasingly less profitable compared to ASICs, and possibly not profitable at all.

Third Claim: "Also, I can always stop mining once my rigs do not profit anymore and just game on them and/or sell the parts individually probably up to 70% of what I bought them for."

Counter Claim:  Sure, if you want to game on them fine.  But then you're not really buying them "for mining", so this entire discussion is pointless.  Regarding selling the hardware...  you could also sell your ASIC miner.  The only thing that will replace an ASIC miner in Bitcoin is... faster, better ASIC miners.  That's a lot like nothing is going to replace GPUs for gaming, except faster better GPU's.  It's reasonable to believe that ASIC miners will retain their value on par with GPUs... perhaps even *more* since they are scarce.

Judgement:  If you're buying them to game, the screw it, buy GPUs.  If it's an investment, you're still better off with ASICs.

http://pcpartpicker.com/parts/partlist/
lowest pricing I could safely suggest I suppose.  Could spend a bit more on mobo or psu if you like. but still 1150.

-could add a DVD drive, HDD and RAM for bout' another 100.
-OS if windows about another 100.

Hmm good point, I'll look into it.

I agree.

I mean even if difficulty goes up, it is possible that BTC/LTC will continue to rise so there ROI will still be there.

Also, I can always stop mining once my rigs do not profit anymore and just game on them and/or sell the parts individually probably up to 70% of what I bought them for.

I see 7950's going for $250 on craigslist used. But I am buying them brand new at $289 from new egg.

Yes

Keep building GPU miners... the price (and yes the difficulty as well) are still going up.

Build your GPU rigs with the price of btc @ it's all time high, since at a future date, it WILL pass that.

You'll thank me later.

The processor comes with a fan, are you planning on overclocking?

Personally for anything more than two cards I would run in an open air case (crate) with risers. I've seen pictures of three or more cards shoved in a PC case and cooling has to be a nightmare...

Have you looked through the pictures of rigs thread for ideas? https://bitcointalk.org/index.php?topic=7216.2120

LOL don't listen to any of these liars. BTC mining has been more profitable then it has in over a year, but don't mine BTC. Its a wasted investment. This right here is why I refuse to buy anything ever again on these forums

I use to be happy with a 6 month ROI. Now we are about 3 months on gpu's

LTC?

http://pcpartpicker.com/p/Sal7

This is the parts my brother and I are gonna split.

Thoughts?

AlphaWolf,

Many thanks for the information and research in your reply.

I understand about the difficulties being adjusted.

However, the costs will be divided between my brother and I so its more like $600 investment.
Second, we are both avid gamers (Starcraft 2 / Diablo 3 etc.) so will definitely still use the computers even after they become inefficient in mining.

The way I see it, invest in a decent rig, make a few bitcoins, then enjoy the computer and resell the extra video card.

But again, I 100% agree with what you are saying about the diminishing returns mining the bitcoins.

Just to add I also invested in bitcoin (buying in at $66). But I also want to diversify instead of just put my capital + the capital of the computer straight into bitcoin.

If I have $5000 and bought bitcoin at $66 like I did, I am sitting on a pretty decent profit. However, if Bitcoin does go below $66, I would like to have "something to show for it" which would be the computers.

So with that in mind, I ended up investing a portion into bitcoin already @ $66 entry point and allocating $1200 or so (split between my brother and I) for a computer.

Hope that makes sense and also thank you for your post it does clear up a lot of things and will definitely be of useful information to other readers out there with questions.

All too entirely true if the OPs goal is pure investment. I don't know because he only asked about hardware.

There are other scenarios. Look at it from the perspective of a gamer, or a computer hobbyist. Coming out with 6.57940808 BTC AND three GPUs after 14 weeks?

SELL the BTC $800
SELL one GPU $200
KEEP two GPU and crossfire for a nice gaming rig for about $100

Again what you wrote is worth reading and I hope the OP understands because that is the reality from an investment perspective.

Why on earth do people insist on spending > $1k on GPU's for mining?  Has no one been paying attention?  Do people like to lose money?

This model will be a bit simplistic, but follow along...

Let's say you overclock and get the high-end production out of each GPU..  600 MH/s.  So you get 1800 MH/s total.
(reference here: https://en.bitcoin.it/wiki/Mining_hardware_comparison)

Each card uses 200W of power.  That's 600W just for the cards.  Figure 80% efficiency PSU (if you even have an 80% PSU) means you're burning a minimum of 750W, not counting CPU, RAM, HD, motherboard circuitry...

Conservatively you're going to spend at least $1100 on hardware.  Now head over to here and plugin those numbers:
http://www.bitcoinx.com/profit/

Wow, it looks like you're going to "profit" $9.43 USD per day! Wait.. but over on the "net profit" side, it says you've *lost* $304.30 USD over the first 3 months.

Now look at how quickly the difficulty is going up:
http://bitcoindifficulty.com/

And think about just how long you're going to be "profiting" anything near $9.43 per day with the difficulty going up like that.  Every two weeks, you will make less. The prediction of only being in the hole $300 after the first 3 months is a vast understatement.  The maximum value of a share dropped 14% at the last adjustment.  Let's see how that makes the numbers work:

Starting at an "Income" of $12.13 USD/day and power cost of $2.70 USD/day.  For simplicity I'll just put $37.80 each 2 weeks for power, since this doesn't change.

After 2 weeks: ($12.13 * 14) - ($37.80) = $132.02
After 4 weeks: ($10.43 * 14 - ($37.80) = $108.22
After 6 weeks: ($8.97 * 14) - ($37.80) = $87.78
After 8 weeks: ($7.71 * 14) - ($37.80) = $70.14
After 10 weeks: ($6.63 * 14) - ($37.80) = $55.02
After 12 weeks: ($5.70 * 14) - ($37.80) = $42.00
After 14 weeks: ($4.90 * 14) - ($37.80) = $30.80

Grand total "profit"  after 14 weeks: $525.98
Minus Cost of system: $525.98 - $1100 = -$574.02

EVEN IF you don't pay for electricity, you're still in the hole $309.42 after 14 weeks.

And that's assuming BTC is still at $120 USD in three months...

The calculator estimates you'll make 0.1009 BTC per day at current network difficulty.  This will of course drop every 2 weeks also.
0.1009 * 14 = 1.4126
0.086774 * 14 = 1.214836
0.07462564 * 14 = 1.04475896
0.06417805 * 14 = 0.8984927
0.05519312 * 14 = 0.77270368
0.04746608 * 14 = 0.66452512
0.04082083 * 14 = 0.57149162

Total BTC after 14 weeks: 6.57940808

Total BTC if you just spent $1100 on BTC (at current rate of $121 USD): 9.090909

If you've got $1100 burning a hole in your pocket, invest in an ASIC miner, an ASIC mining contract, or straight up buy some BTC.  Buying GPUs to make BTC is the worst possible investment.

Sure no reason not to salvage old parts, just don't cheap out on the power supply, it's as important as the video cards.

I think I can save even more money.

I'll use my OLD PC's Hard Drive and RAM. Has Win 7 so no need to buy that.

So looks like I'll just need a MB/CPU/PSU/ and the 3 GPU's.

Somewhere around $1300 including tax if you use a crate for an enclosure and get free shipping. Grab a spare hard drive or boot from usb.

3x GPU $900
$150 CPU/RAM/MB (maybe hard to pull off but possible if you go cheap)
$150 PSU

If any of you kind sirs have spare time to post a template of a decent mining rig with 3 x 7950's?

Just trying to see how much to expect to pay. (I'll be building it myself).