I am starting a 189G/Hash Mining RIG

[gigahash]

I and a few fellow members are thinking of setting up a big mining rig, specifically using ATI Radeon 6990 x3 per computer.

Total 189G/Hash

the amount i get from the bitcoin calculator is

11 hrs for mining a block
3000 bitcoins per month

is this accurate or ?

[server]

http://bitcoinx.com/profit/

[gigahash]

electric is free my friend

also with such a large mining rig, solo is the way right? would 189G/Hash mine 50 coins in 11hrs?? without any issues or drawbacks?

[gigahash]

why is no one being helpful and advising me, i am being serious... this is not a joke...

my investment would be 70000$ and return according to the calculators is atleast 200-250k - costs = 120k-150k profit

[SgtSpike]

Yes, that would be your return.  I can't imagine anywhere with that much free electricity though.  A school, maybe?  A giant warehouse going unused?

Keep in mind 3 6990's will eat up around 1350w (if my sources are correct).  That means you'll need a separate circuit for each rig, unless you're running on 220v.  In which case, I'm jealous.

[gigahash]

lol not a school or warehouse just a technique i have into attaining electrcitity without issues.

would i have to connect all 90 GPU to one super computer using various motherboards all interconnected like a web?

can someone get into more detail in regards to how my rig would be setup, so all power is in ONE

[SgtSpike]

lol not a school or warehouse just a technique i have into attaining electrcitity without issues.

would i have to connect all 90 GPU to one super computer using various motherboards all interconnected like a web?

can someone get into more detail in regards to how my rig would be setup, so all power is in ONE

A technique for attaining 40kw of free electricity?  You need to teach me this technique!   

No way to connect them all together like that that I am aware of.  Each rig needs to be individually managed.

[bitcoinhead]

Yeah, I think Spike is correct.  Even if you could get a bus that could handle so many cards, power is your big issue here.  You're going to need a bunch of computers with their own power supplies to run something like this.  Think of racks of servers.  There's no feasible way to build a power distribution capability (at least not in a reasonable amount of time, since I assume you'd want to start mining quickly before the reward drops by 50% in 2012 sometime).

And of course even if you can get free electricity (just run a jumper from your neighbor's house! :-)  you're next issue is going to be cooling.  You will need a lot of AC to keep the place from melting down, and that will require not just the AC units, but adequate venting and ducting to ensure that the hot air can escape.  Or maybe a bit water cooling rig....   Big project.

[SgtSpike]

Yeah, I think Spike is correct.  Even if you could get a bus that could handle so many cards, power is your big issue here.  You're going to need a bunch of computers with their own power supplies to run something like this.  Think of racks of servers.  There's no feasible way to build a power distribution capability (at least not in a reasonable amount of time, since I assume you'd want to start mining quickly before the reward drops by 50% in 2012 sometime).

And of course even if you can get free electricity (just run a jumper from your neighbor's house! :-)  you're next issue is going to be cooling.  You will need a lot of AC to keep the place from melting down, and that will require not just the AC units, but adequate venting and ducting to ensure that the hot air can escape.  Or maybe a bit water cooling rig....   Big project.

40kw needs 136,000 BTU's to properly cool, which could require up to 10 tons of A/C power.  That'll tack on another $20k or so to your initial investment.

[gigahash]

how about i build an outdoor computer den lol with fresh air cooling system

[navigator]

DELETED for privacy

[trentzb]

You beat me to it. I was also trying to figure out where to buy 6990s for ~$300.

Assuming you need 189 Gh/s your breakdown would be:

~80 rigs holding 3 x 6990 each.

Per rig: ~$450 + 3 x $500 (being extremely generous) = ~$1950/rig

80 x $1950 = $156k investment not including cooling as SgtSpike mentioned.

189 Gh/s would do you ~100 BTC/day IF difficulty never changed again. At a generous $10/usd per BTC exchange rate you are looking at about $1k per day gross, but net I suppose since you get free electricity.

So ~$31k per month would take you around 5+ months to break even.

navigator and my numbers are in the ballpark, both are pretty accurate...I was just more generous assuming you have a secret source for 6990s at $500 each, exchange rate of $10/BTC and difficulty never changing, ever.

[TeaL]

Yes, that would be your return.  I can't imagine anywhere with that much free electricity though.  A school, maybe?  A giant warehouse going unused?

Keep in mind 3 6990's will eat up around 1350w (if my sources are correct).  That means you'll need a separate circuit for each rig, unless you're running on 220v.  In which case, I'm jealous.

Actually each 6990 under load draws 300W, the 450W statistic on the AMD's website is total system load (including processor etc), not for each card. For a 3 * 6990 rig you would need a 1200W continuous output PSU.

[MiningBuddy]

Yes, that would be your return.  I can't imagine anywhere with that much free electricity though.  A school, maybe?  A giant warehouse going unused?

Keep in mind 3 6990's will eat up around 1350w (if my sources are correct).  That means you'll need a separate circuit for each rig, unless you're running on 220v.  In which case, I'm jealous.

Actually each 6990 under load draws 300W, the 450W statistic on the AMD's website is total system load (including processor etc), not for each card. For a 3 * 6990 rig you would need a 1200W continuous output PSU.

For what it's worth, my 6990's clocked at 920/600 in the overclocked bios switch pull ~420w according to my kill-a-watt.

[gigahash]

thank you all for correcting me on my calculations, i got carried away with the 189g/hash

[trentzb]

Thats full system at wall at ~420W right? What MB/CPU/MEM and perpherals you using, and how efficient is PSU?

I would estimate your 6990 is doing around 300W +/- 20 itself. Sound right?

So you might be able to squeeze 3 x 6990 + system on 1kw PSU, probably better on 1.2kw.

[MiningBuddy]

I actually have 2 6990's in this machine and total it pulls ~920w from the wall on a 1kw 80 star bronze psu so +/- ~20%
It's just a bare 890fx mobo with 2gb ram and a Sempron 140, though it does have a 1tb sata hdd which I will be swapping for a usb stick as soon as it arrives.
1200w should be fine for 3x6990's