help building a gpu mining rig

[shilex]

i calculated a 3k rig with 5 7950 in it would earn me like 700 a month with btc i think i can make a profit after like 4 or 5 months no?

[clicksmoney]

i calculated a 3k rig with 5 7950 in it would earn me like 700 a month with btc i think i can make a profit after like 4 or 5 months no?

4-5 months if everything stays the same. Difficulty will increase possibly faster than the default calculator numbers. If your plan is to get BTC while you still effectively can through GPU mining go ahead. Just don't be too set on that far down the line with setting those amounts as a cash flow. Can you afford to be wrong with a 3k rig or should you go to ASIC and wait, using the power you save to do trading may get you higher numbers.

Food for thought. BTCTC forever.

[FTWbitcoinFTW]

You need to include in your calcul the next release of ASCI...

So make difficulty x10 at least for a good ROI calcul



http://www.bitcoinx.com/profit/

Diff : 70.000.000 
Power : 800?
Time frame : 1 month 
Cost hardware : 4000$
Hash rate : 3500?
Electricity rate : 0.21 (belgium)

Code:

Coins per 24h at these conditions 	0.0249 BTC
Power cost per 24h 	4.80 USD
Revenue per day 	3.49 USD
Less power costs 	-1.31 USD
System efficiency 	4.38 MH/s/W
Mining Factor 100 at the end of the time frame 	0.10 USD/24h@100MHash/s
Average Mining Factor 100 	0.10 USD/24h@100MHash/s
Power cost per time frame 	146.10 USD
Revenue per time frame 	103.95 USD
Less power costs 	-42.15 USD

So if ASCI come in the next 3 month, you'll lose money !!

BUT yes, if you start TODAY, you'll make profit but for how long time ?

[ZanderD]

BFL seems legit. Im going with them.

[shilex]

FTWbitcoinFTW  thx for the help, i got a motherboard cpu and mem laying around so i only need to buy a gfx and a nice psu so i think it is worth the risc...

[FTWbitcoinFTW]

FTWbitcoinFTW  thx for the help, i got a motherboard cpu and mem laying around so i only need to buy a gfx and a nice psu so i think it is worth the risc...

Yes, but don't focus on BTC. With ASCI on the way...
Anyway, with small work you can switch to any altcoin so i thinks it's never bad  to start mining (without put in 3k€)

BFL seems legit. Im going with them.

[shilex]

i just got my test rig setup strike extreme asus motherbord i think a core 2 duo cpu 2gig off mem and a 160 hdd

now lets find a cheap 7950

[whizz94]

I'd caution against buying kit solely for bitcoin mining.
Get approximately what you want for your other computing tasks, but modify the parts list so that it works when making bitcoin.
For example, I already had an i5-2500 on an "ordinary" motherboard which came with 16x graphics ports.  Those graphics ports are a must-have.
It was working with a smallish nvidia graphics card, which I've just swapped for an ATI 6670 (not a bitcoin specialist) - the graphics card which you wanted would be much better.  Anything with 1GB or more of GDDR5 memory from ATI seems to suit the algorithm.
You'd also want to be more careful than usual about choosing a power supply.  Having a midrange graphics card drawing about 50 Watts, I don't worry about that, but for bigger GPU cards you'll want more and you'll want enough 12V power connectors.

I also put in an OCZ solid state hard drive (nice extra if quieter more reliable and faster hard drive operation is on your wish list) and spent a day or two putting in Xubuntu12.04 i686 and signing up various things like my bitcoin miner identity at a mining pool website.  It did nothing yesterday, but selecting ATI lastest proprietary drivers and it is now working ok at one pool but not at another.

Goal now is to leave it logged in and making bitcoin while I do something else on that computer.

[shilex]

my main gaming rig is ok it has a ocz ssd and i7 so the parts i have are just sparse so why not build a mining rig...

[mushly]

my main gaming rig is ok it has a ocz ssd and i7 so the parts i have are just sparse so why not build a mining rig...

The speed of your disk and CPU have absolutely no bearing on mining capability. You need AMD graphics cards.

[shilex]

i know that is why i am not going to put in a amd gfx in my main pc, only in my pc where i am going to mine one

[whizz94]

Since the front page of the Financial Times showed the bitcoin price chart to all the banksters last week, I'd expect them to be plotting to bounce the bitcoin price.  They've done that to the share price of billion dollar companies before now, and trashed the currency of smaller countries, so don't think that they won't try it.  This makes it a rather uncertain time to go spending big £ on mining hardware.  I'm getting more pennies of BTC out of a 6670 single GPU than pennies of electricity going in.  My main target is to buy renewable energy making hardware over the long term.  Short term pennies per hour output per £k spent is less but 20+ years of rising energy costs are a certainty.

Recommendation is to work with what you have, set it GPU mining, but don't buy kit solely for hope of making bitcoin profits for personal self-aggrandisement.
If you still want hardware recommendations, I could look up 4x PCIEx16 motherboards for you at 0.4 BTC per hour, expecting to find something suitable for you in one hour.

Lastly, be sensible with power supplies.  Dynamic or automatic power factor correction is worth having.