Building a Mining Rig - Specs

[lego23]

I'm thinking of building a mining rig and would like to know what you guys think.

GPUs: 5x ATI 5770s @ $110 http://www.newegg.com/Product/Product.aspx?Item=N82E16814131330&cm_re=5770-_-14-131-330-_-Product
MOBO: $180 http://www.newegg.com/Product/Product.aspx?Item=N82E16813130274
CPU: AMD 2.8Ghz Single-Core @ $44 http://www.newegg.com/Product/Product.aspx?Item=N82E16819103888&cm_re=am3_processor-_-19-103-888-_-Product
Ram: 4GB @ $50 http://www.newegg.com/Product/Product.aspx?Item=N82E16820145328&cm_re=ddr3_ram_4gb-_-20-145-328-_-Product
PSUs: 2x 1080W @ $80each http://www.newegg.com/Product/Product.aspx?Item=N82E16817339035
HDD: 500GB @ $39 http://www.newegg.com/Product/Product.aspx?Item=N82E16822145299
Case: Cheap Apex case @ $20 http://www.newegg.com/Product/Product.aspx?Item=N82E16811154095
OS: ubuntu

Total: about $1,100

I figured about 875MHash/sec.  

Is there a cheaper motherboard that will support 5 5770s?  Do I only need one PSU?  How do I calculate the electricity costs?  Also, any tips on cooling this system?

Thanks

[1715265385]

1715265385

[1715265385]

1715265385

[1715265385]

1715265385

[Ian Maxwell]

If I were you I'd take that $1100 and just buy as many bitcoins as you can. That's what I wish I'd done last month.

[[Tycho]]

GPUs: 5x ATI 5770s @ $110 http://www.newegg.com/Product/Product.aspx?Item=N82E16814131330&cm_re=5770-_-14-131-330-_-

Are you sure it's a single-slot card ? May be it's better to plug 2x5970 in a cheap MB, single PSU and get ~1150 MH/s ?

PSUs: 2x 1080W @ $80each http://www.newegg.com/Product/Product.aspx?Item=N82E16817339035

You don't need two PSUs for that. A good 1200+W may be enough (and more effective if 80PLUS).

[eleuthria]

79.5 cents/mHash on that rig, and I think you're going to run into big issues cooling 5 GPUs inside that tiny case with poor air flow both from case design and cramming cards in.

My latest rig ended up costing $811 after tax/shipping, 2x 5870s, and the final cost was 93 cents/mHash capacity, while using SIGNIFICANTLY less wattage than what 5x 5770s will run.

Case: HAF 922 ($100)
PSU: Cooler Master 750W ($98)
Motherboard: MSI AM3 ($70)
Processor: Sempron 140 ($38)
RAM: 1 gig Kingston ($13)
Hard Drive: Kingston 16 GB SSDNow ($50)
GPU 1: GigaByte ATI Radeon HD 5870 ($220)
GPU 2: MSI Lightning ATI Radeon HD 5870 ($222)

Just hunt on NewEgg & Amazon for 5870s once or twice a day.  They tend to pop up cheap (< $230) and sell out within a few hours.

The case is a bit overkill, but I like using cases that are designed for maximum airflow to keep the cards running cooler at higher clock speeds, leading to better mHash/watt ratio, both in terms of power consumption from the GPUs, and the amount of heat that will have to be offset by my air conditioner.

[lego23]

GPU 1: GigaByte ATI Radeon HD 5870 ($220)
GPU 2: MSI Lightning ATI Radeon HD 5870 ($222)

Just hunt on NewEgg & Amazon for 5870s once or twice a day.  They tend to pop up cheap (< $230) and sell out within a few hours.

What is the difference between all of the different 5870s?  Are they all about the same?

[eleuthria]

GPU 1: GigaByte ATI Radeon HD 5870 ($220)
GPU 2: MSI Lightning ATI Radeon HD 5870 ($222)

Just hunt on NewEgg & Amazon for 5870s once or twice a day.  They tend to pop up cheap (< $230) and sell out within a few hours.

What is the difference between all of the different 5870s?  Are they all about the same?

I'll be able to tell you on Wednesday how the MSI Lightning compares to the Gigabyte.  My main 2 rigs both use GigaByte 5870s.  The rig I linked is about to be hooked up, waiting on the power supply to show up.  I also just bought another MSI Lightning on NewEgg this morning (bought 1 and they were out of stock before I could buy a 2nd for a complete rig).

My understanding is that all the 5870s are BASICALLY the same performance.  Slight variations, mostly due to temperatures you can run them out with the slight changes in how each the fans/heat sinks are set up between brands.  I do know that you want 1 gig cards over 2 gig cards due to the savings in power consumption.

[freeloader247]

How about this mobo:
http://www.newegg.com/Product/Product.aspx?Item=N82E16813130274
With
2x5770:
http://www.newegg.com/Product/Product.aspx?Item=N82E16814131330&cm_re=5770-_-14-131-330-_-Product
3x5850:
http://www.newegg.com/Product/Product.aspx?Item=N82E16814150499&cm_re=5850-_-14-150-499-_-Product

[lego23]

How about this mobo:
http://www.newegg.com/Product/Product.aspx?Item=N82E16813130274
With
2x5770:
http://www.newegg.com/Product/Product.aspx?Item=N82E16814131330&cm_re=5770-_-14-131-330-_-Product
3x5850:
http://www.newegg.com/Product/Product.aspx?Item=N82E16814150499&cm_re=5850-_-14-150-499-_-Product

Why would you choose this setup over 5x 5850s?

[grndzero]

How about this mobo:
http://www.newegg.com/Product/Product.aspx?Item=N82E16813130274
With
2x5770:
http://www.newegg.com/Product/Product.aspx?Item=N82E16814131330&cm_re=5770-_-14-131-330-_-Product
3x5850:
http://www.newegg.com/Product/Product.aspx?Item=N82E16814150499&cm_re=5850-_-14-150-499-_-Product

Why would you choose this setup over 5x 5850s?

4 5850's would be the max you can have in any system.