So I just bought a rig, but I feel like im doing something wrong...

[clonedone]

heres what i bought:

VID CARDS MSI R6990-4PD4GD5 Radeon HD 6990 4GB 256-bit GDDR5 PCI Express 2.1 x16 HDCP Ready CrossFireX Support Video Card with Eyefinity X3
   
PROCESSOR AMD Athlon II X2 255 Regor 3.1GHz Socket AM3 65W Dual-Core Desktop Processor ADX255OCGMBOX

WIFI CARD TP-LINK TL-WN722N USB 2.0 High Gain Wireless Adapter

HARD DRIVE SAMSUNG EcoGreen F2 HD103SI 1TB 5400 RPM SATA 3.0Gb/s 3.5" Internal Hard Drive -Bare Drive

RAM Kingston ValueRAM 2GB (2 x 1GB) 240-Pin DDR3 SDRAM DDR3 1066 (PC3 8500) Dual Channel Kit Desktop Memory Model KVR1066D3N7K2/2G

MOBO MSI 890FXA-GD70 AM3 AMD 890FX SATA 6Gb/s USB 3.0 ATX AMD Motherboard

POWER SUPPLY OCZ ZX Series OCZ-ZX1250W 1250W ATX12V v2.2 / EPS12V SLI Ready CrossFire Ready 80 PLUS GOLD Certified Modular Active PFC ...

CASE Antec DF-85 Black ATX Full Tower Computer Case

Grand total of $2,964.93

So I am planning on installing windows 7 64bit ultimate on this machine (im not familiar with linux)
I am going to just plug this computer in without moniter or keyboard or mouse and im gonna use LOGMEIN to run this thing after its set up.
and im hoping for atleast 2000 Mhash from this machine with phoenix miner

I also used an electricity calculator @ .18 cents per kilowatt (NYC) and measured $151 per month in electricity. which I hope is correct, i just ran the calculator with 1200 watts per hour.


But am I missing something vital here? Im new to mining, I have mined with my crappy gt240 card on my computer, so i understand the jist of it.
Will i need some extra software to work all three video cards?
 

[rezin777]

It is probably going to take a while to pay that machine off.

Also, I think windows will only recognize 4 GPUS?

[goatpig]

But am I missing something vital here? Im new to mining, I have mined with my crappy gt240 card on my computer, so i understand the jist of it.
Will i need some extra software to work all three video cards?

3*6990 = 6 gpus. Windows only supports up to 4

[Jaime Frontero]

It seems like you've over-spec'ed some components - for a dedicated miner.

But I see problems with heat and power.  Three (three, right?) of those 6990s running full-bore will chew up at least 1200 Watts - but your PS is only a 1250.  Not groovy.

Also, the case you've chosen only has fan controls for the front fans.  Once you get your power supply situation sorted out, you're going to have about 1500 Watts of heat to dissipate.  I have my doubts that the Antec case - unmodified - will handle that.  You'll definitely want the optional side fan - but don't get the Antec: get a good aftermarket fan with a speed control, and replace the rear fans with controllable fans as well.

With three of those 6990s, you're probably going to be thinking about waterblock cooling pretty quick - or running with an open case and a bunch of jury-rigged external fans.

Don't even think about adding a fourth card (there's room...) until you've got three under control.

[JJG]

Yikes, I hope you have another use for that machine other than mining.

Remember that the difficulty goes up every two weeks, meaning your BTC income will drop every two weeks.

In my forecasts, I assume that difficulty will go up 15% every 2 weeks. This is somewhat reasonable, although unexpected changes can throw this value around wildly.

I also assume that hardware will depreciate about 5% each month. In the short run, your hardware has already depreciated much more than this, but depreciation slows down over time.

Finally the BTC/USD exchange rate is wildly fluctuating. For this exercise let's assume it will be 2.0 for the next year.

Anyway, putting your hardware cost, electricity cost, and expected mhashes/sec into my rough model shows that you will never break even with this rig at this exchange rate. In fact, your overall value (USD income + depreciated hardware value - electricity costs - initial hardware costs) peaks around month 4. After that, difficulty increases enough that your electricity costs and hardware depreciation are larger than BTC income.

Now if BTC/USD goes to ~3 and stays there, and difficulty only increases at 10%/month (unlikely at 3:1 BTC:USD) then you might break briefly break even, but that's pretty speculative.

[clonedone]

But am I missing something vital here? Im new to mining, I have mined with my crappy gt240 card on my computer, so i understand the jist of it.
Will i need some extra software to work all three video cards?

3*6990 = 6 gpus. Windows only supports up to 4

then the ubuntu will support 6 cores?


also, the other guy talking about difficulty, then no one will ever profit from mining in your case, because three 6990s seems just about top of the line, just how much more will allow a mining rig to finally be profitable? your claiming that every two weeks, the btc will go down, then in about a year, i would be bringing in around 50 - 100 btc instead of 210 btcs(30 btc per day with three 6990's) every week.
50-100 btc dosent cover much especially since electricity is $151 per month.
basically what your saying is that mining is useless right?
but if mining is useless, then the btc network will fail.
so I dont get it. anyone concur with what JJG is talking about?

[JJG]

...
also, the other guy talking about difficulty, then no one will ever profit from mining in your case, because three 6990s seems just about top of the line, just how much more will allow a mining rig to finally be profitable? your claiming that every two weeks, the btc will go down, then in about a year, i would be bringing in around 50 - 100 btc instead of 210 btcs(30 btc per day with three 6990's) every week.
50-100 btc dosent cover much especially since electricity is $151 per month.
basically what your saying is that mining is useless right?
but if mining is useless, then the btc network will fail.
so I dont get it. anyone concur with what JJG is talking about?

Plenty of people will profit from mining, but it isn't the people buying cutting-edge hardware and running it in locations with high electricity costs.

Electricity rates are less than $0.08 / kWH in some parts of the US, and the 6990 is not the best bang-for-the-buck mining card. You're going up against miners who can buy 3 used 5970 cards and some other used hardware for $1800 total and pay less electricity costs than you over the course of the year.

And if difficulty increases at a steady rate of 15% every two weeks (big wildcard here, but it's a reasonable fit for the recent trend) then your rig that generates 30BTC/day now will actually generate closer to 1 BTC/day in 1 year (24 increases of 15% each). If the difficulty only increases at a rate of 10%, then it will still only generate 3 BTC/day. If the planets align for you and the increase is only 5%/period, then you're still only looking at 9.3 BTC/day.

Meanwhile, the exchange rate could go up. But even then you'd be better off just trading your USD for BTC right now.

[Garrett Burgwardt]

Other people (like me) who have beefy computers for games already also make a profit, because initial costs are effectively zero (as I would have gotten a 6990 anyway)

[clonedone]

...
also, the other guy talking about difficulty, then no one will ever profit from mining in your case, because three 6990s seems just about top of the line, just how much more will allow a mining rig to finally be profitable? your claiming that every two weeks, the btc will go down, then in about a year, i would be bringing in around 50 - 100 btc instead of 210 btcs(30 btc per day with three 6990's) every week.
50-100 btc dosent cover much especially since electricity is $151 per month.
basically what your saying is that mining is useless right?
but if mining is useless, then the btc network will fail.
so I dont get it. anyone concur with what JJG is talking about?

Plenty of people will profit from mining, but it isn't the people buying cutting-edge hardware and running it in locations with high electricity costs.

Electricity rates are less than $0.08 / kWH in some parts of the US, and the 6990 is not the best bang-for-the-buck mining card. You're going up against miners who can buy 3 used 5970 cards and some other used hardware for $1800 total and pay less electricity costs than you over the course of the year.

And if difficulty increases at a steady rate of 15% every two weeks (big wildcard here, but it's a reasonable fit for the recent trend) then your rig that generates 30BTC/day now will actually generate closer to 1 BTC/day in 1 year (24 increases of 15% each). If the difficulty only increases at a rate of 10%, then it will still only generate 3 BTC/day. If the planets align for you and the increase is only 5%/period, then you're still only looking at 9.3 BTC/day.

Meanwhile, the exchange rate could go up. But even then you'd be better off just trading your USD for BTC right now.

well this is very troubling to hear, but thanks for the input. If what you predict does end up happening, I plan to sell two 6990s and turn the computer to a gaming computer for myself, as I am really tired of my gt 240 lol.

anyway, the problem of the windows only supporting 4 gpus, what will happen when i put in the third card? will it just not recognize it?
also i hear that 6990 has no driver for linux, so is there any way right now that i can run three 6990s?
I notice on http://www.bitcoinrigs.com/ they sell computers with 3 6990s. what OS do they use to run all of them?

[foxmulder]

Read this thread : http://bitcointalk.org/index.php?topic=5764.0 , i haven't run my quad 6990 yet but dual 6990 works fine on ubuntu 10.04.

[ghost]

Read this thread : http://bitcointalk.org/index.php?topic=5764.0 , i haven't run my quad 6990 yet but dual 6990 works fine on ubuntu 10.04.

You have dual 6990s on Ubuntu? I have the same setup but I can't get the second core on the first card to work. Both cores on the second card work. All 4 show do show up.

[clonedone]

Read this thread : http://bitcointalk.org/index.php?topic=5764.0 , i haven't run my quad 6990 yet but dual 6990 works fine on ubuntu 10.04.

cool i never used linux but ill be sure to find out now.
btw you only get 333 mhash on ur 6990? I thought 6990 gets around 640 mhash?

[proudhon]

Read this thread : http://bitcointalk.org/index.php?topic=5764.0 , i haven't run my quad 6990 yet but dual 6990 works fine on ubuntu 10.04.

cool i never used linux but ill be sure to find out now.
btw you only get 333 mhash on ur 6990? I thought 6990 gets around 640 mhash?

It's 333x2.  Each GPU of the 6990 is doing 333Mhash/s, and there are 2 GPUs.