Need input on new bitcoin rig with 4x7790

[spinx]

Hi, im spinx from Sweden!

I have known about bitmining for some time now but never really botherd. Then yesterday i notice an articel about the increasing value of bitcoins. That made me interested I have access to "free" power at my place so powerconsumption is not really an issue at this stage.

First of i want to know the answer to the obvious question "is it really worth it"? What are the main issues here?

I also configured an idea of a bitmining rig, looks like this so far, please give me input!

* 4 x SAPPHIRE RADEON HD7790 1GB PCI-E DVI/HDMI/DP
* GIGABYTE GA-990FXA-D3 AM3+ ATX
* AMD SEMPRON 145 2.8GHZ 1MB SOCKET AM3 BOX
* CORSAIR 4GB DDR3 XMS3 INTEL I3/I5/I7 1333MHZ
* CORSAIR CX 750W BRONZE ATX12V 2.3 PSU
* Build my own open air case

Total price in Sweden : 7500SEK = 1150USD.

Data from blockchained.com mining profitability calculator:

• Bitcoin difficulty: 6695826
  Generated coins per block: 25
  Conversion rate: 127.54000
  Hash rate: 4x295(found this number here in a thread) =  1180 MHash/s    = 1.18 GHash/s
  Electricity rate: 0 USD/kWh
  Power consumption: about 5-600W

Profitability Estimate

• Time frame: 3 months
  Cost of mining hardware: 1150 USD
  Decline per year: 0,63 default: 0.63 (from Moore's law: 0.5 every 18 months).
  Revenue per time frame: 974.78 USD
  Hardware break even: 109 days
  Net profit first time frame: -175.22 USD
  

This estimates to a profit of 2156.24 USD for the first year after the hardware has been paid off. Is this a good number?
I also found 7850's for about 200USD/pcs, maybe 4 of them would be better?

Cheers!

[lbr]

Is 7790 available in Sweden?
Can you point me to the store plz?

[spinx]

Is 7790 available in Sweden?
Can you point me to the store plz?

There are several shops who has them, but the most reliable one is DustinHome
http://www.dustinhome.se/product/5010675358/sapphire-radeon-hd7790-1gb-pci-e-dvi-hdmi-dp/

[lbr]

Is 7790 available in Sweden?
Can you point me to the store plz?

There are several shops who has them, but the most reliable one is DustinHome
http://www.dustinhome.se/product/5010675358/sapphire-radeon-hd7790-1gb-pci-e-dvi-hdmi-dp/

That's 50$ more than MSRP..
Probably 7790 is too 'hot' now)

[spinx]

Is 7790 available in Sweden?
Can you point me to the store plz?

There are several shops who has them, but the most reliable one is DustinHome
http://www.dustinhome.se/product/5010675358/sapphire-radeon-hd7790-1gb-pci-e-dvi-hdmi-dp/

That's 50$ more than MSRP..
Probably 7790 is too 'hot' now)

The RSP for 7790 in Sweden is 199USD (1299SEK) so this price of 1295 is spot on. I dont know where u live, but in Sweden the RSP is always about +25% compaired to US. The cheapest price in Sweden atm is 186USD and i dont think it will drop that much in the near future. I found that there are 7850's selling for 200USD here, they consume abit more watt's but as thats not a concern for me, the benefit of 30-40% more calculating power might be a good investment?

[litecoin_messiah]

do you think "CORSAIR CX 750W BRONZE ATX12V 2.3 PSU" will be enough for 4 graphics cards?

[spinx]

do you think "CORSAIR CX 750W BRONZE ATX12V 2.3 PSU" will be enough for 4 graphics cards?

According to guru3d the 7790 has a "Subjective obtained GPU power consumption = ~ 90 Watts"
http://www.guru3d.com/articles_pages/radeon_7790_review_benchmark,6.html

Numbers from guru3d's review:

System Wattage with GPU in FULL Stress = 179W
 + 3 x 90W = 270W
= 449W

449W = 60% utilization of 750W , so i guess thats allright with the 7790's?

[Ledningen]

Why not get a 6950 used if you can find it? 420 ish hash rate and it's cheap. Or 2x 7950 that will do 1.2+ Gh/s. @ 160watt pr. card.

If you dont pay for power, get the most hashrates you can. A 7950 will also be much more easy to sell again in the future, at a reasonable price point.

[spinx]

Why not get a 6950 used if you can find it? 420 ish hash rate and it's cheap. Or 2x 7950 that will do 1.2+ Gh/s. @ 160watt pr. card.

If you dont pay for power, get the most hashrates you can. A 7950 will also be much more easy to sell again in the future, at a reasonable price point.

Greate idea just ordered a new system --> 4 x Radeon HD 7950 OC
https://bitcointalk.org/index.php?topic=169841.msg1765919#msg1765919