<a href="http://www.reddit.com/r/Dogecoinmining/comments/1ttrn5/the_holy_grail_of_mining_rigs_2_important_metrics/" target="_blank">http://www.reddit.com/r/Dogecoinmining/comments/1ttrn5/the_holy_grail_of_mining_rigs_2_important_metrics/</a>

<div class="quote-container"><span>Quote:</span>

<div class="quote-block">There are many guides all over the 'net for building a mining rig.<br>

The "holy grail" of any mining rig is to have:<br>

1. the highest hash-rate-to-purchase-costratio and<br>

2. the highest Kh/s-to-watt ratio.<br>

Starting with the first metric: If you build this 6 GPU mining rig with the suggested R9 270, you will have a hash-rate-to-cost ratio of 1.5 hashes-per-dollar (2,700Kh/s divided by $1,800). However, if you build the same rig with five of the R9 280x (suggested alternative GPU in the guide), you will have a lower (worse) ratio of 1.42 (3,700 divided by $2,600). So even though you get a higher hash rate from the R9-280x vs the R9-270, the R9-270 is the better deal. Based on this first metric, here is a cost analysis for a build with each of these cards using a base hardware cost of $370 for motherboard/cpu/ram/hdd/etc and only modifying the cards and the psu(s):<br>

* 6x AMD R9-270 | $200/ea | 1.3kw psu | total: $1.8k | ratio: 1.5<br>

* 6x AMD R9 270x | $250/ea | 1.3kw psu | total: $2.1k | ratio: 1.3<br>

* AMD R9 280 (why isn't this card released? should be a rebranded 7950 according to tech powerup<br>

* 5x AMD R9 280x | $400/ea | 1.6kw psu | total: $2.6k | ratio: 1.42<br>

* 4x AMD R9 290 | $600/ea | 1.6kw psu | total: $3.1k | ratio: 1.06 * 4x AMD R9 290x | $670/ea |1.6kw psu | total: $3.1k | ratio: 0.82 * 5x AMD 7970 | $475/ea |1.6kw psu | total: $3.1k | ratio: 1.2 * 3x AMD 7990 | $1k/ea |1.6kw psu | total: $3.1k | ratio: 1.1<br>

Moving on to the second metric: Here's a list of commonly used mining GPU's with their associated Kh/s-to-watt ratio, assuming average results with under-volting. Higher is better:<br>

* AMD R9 270 - Kh/watt: 3 - 150w/ea - $200/ea<br>

* AMD R9 270x - Kh/watt: 2.5 - 185w/ea - $250/ea<br>

* AMD R9 280 (unreleased... re-branded 7950 according to tech powerup<br>

* AMD R9 280x - Kh/watt: 2.7 - 250w/ea - $400/ea<br>

* AMD R9 290 - Kh/watt: 2.75 - 300w/ea - $600/ea<br>

* AMD R9 290x - Kh/watt: 2.7 - 300w/ea - $670/ea<br>

* AMD 7970 - Kh/watt: 2.65 - 270w/ea - $475/ea<br>

* AMD 7990 - Kh/watt: 2.85 - 470w/ea - $1,000/ea<br>

Based on both metrics, the R9 270 wins first place.</div>

</div>

<br>

I think undervolted R9 290 (to about 200W) is the best value if you can get it for $400-450 and intend on packing over two R9 270 GPUs. R9 290 = two R9 270s basically. I highly doubt R9 290 is using 300W.<br><br>

The poster also omitted the cost of additional motherboards, if you were to dump money on six R9 270 GPUs, that would be $1,080 - $1,260 , plus you would need risers. Three R9 290s would do roughly the same and run anywhere from $1,200 to $1,350 and you wouldn't need to buy another 80+Gold/Platinum PSU (~$100-150)/mobo (~$60)/RAM (~$50)/CPU(~$30-50) combo for a second system.<br><br>

R9 270: 6 x 150W = 900W<br>

R9 290 : 3 x 200W = 600W assuming undervolted 200W, 3x 250W = 750W<br><br>

i.e. : SeaSonic X-850 Gold ~$160, EVGA SuperNOVA 1000 P2 1000W 80+ Platinum = $160-200<br><br>

Second source: <a href="http://www.coinminingrigs.com/budget-mining-rig/" target="_blank">http://www.coinminingrigs.com/budget-mining-rig/</a> (via <a href="http://www.reddit.com/r/Dogecoinmining/comments/1trxn3/updated_budget_dogehouse_guide_sub1k_build/" target="_blank">http://www.reddit.com/r/Dogecoinmining/comments/1trxn3/updated_budget_dogehouse_guide_sub1k_build/</a>)

<div class="quote-container"><span>Quote:</span>

<div class="quote-block">As of the date this guide was updated (12/26/2013), a 3 GPU Litecoin mining rig like this, can generate over $250 USD worth of Litecoins per month.<br>

...<br>

Essentially, a Litecoin mining rig is a custom-built PC with parts chosen for maximum hash rates (determines how fast you can mine) and minimal overall cost. Here are the parts you’ll need to build this budget sub-$1,000 rig.<br><br>

Power Supply – $140 - Corsair 850 Watt Gold Rated PSU.<br>

Motherboard – $95 – ASUS M5A97. This motherboard has two of the 16x PCI-e slots and two of the 1x PCI-e slots. All four slots can be used for mining GPU’s. If it is out of stock, this one or this one are good alternatives.budget-litecoin-bitcoin-mining-rig<br>

GPUs – $600 (3x $200) – AMD Radeon R9 270 - For specific configuration details be sure to read this litecoin mining hardware comparison.<br>

Powered Risers – $30 (3x $10) Use 1x to 16x powered risers suspended above the motherboard with proper spacing for cooling the cards. You can get away with non-powered risers for rigs with up to 3 GPU’s, but I usually recommend going with powered risers if the price is similar as it reduces the strain on your motherboard.<br>

CPU – $35 - AMD Sempron 145 Processor Since CPU specs have no effect on mining efficiency, we’ve chosen the cheapest option here.<br>

RAM - $40 – 4GB Kingston DDR3 RAM<br>

Hard Drive – $40 - 32GB Solid State Drive or boot BAMT from a fast USB thumb drive)<br>

Case - $6 - Plastic Milk Crate (you might be able to pick one of these up at your local office supply store for less)<br>

Power Switch - $6 – A basic Motherboard Power Switch does the trick, making it easier to start up your mining rig.<br>

Extra Cooling - $30 - Box Fan (good supplemental cooling for a mining rig, as it pushes all that hot air away from the cards)<br>

Operating System - $0-$90 - Windows 7 is my preference, but if you’re familiar with Linux you can of course download it for free (some folks consider Linux to be the best OS for litecoin mining, since it keeps your overall costs down, improving your litecoin mining ROI or return-on-investment). If you will be loading the operating system from a CD or DVD, a $29 external USB powered DVD drive will come in handy.<br>

Monitor, Mouse and Keyboard (to install the OS and configure the mining software, no need to buy more than one set since you only use this for setup)<br>

Total Cost: ~$980 minus the extra cooling and optional operating system costs.</div>

</div>

<br>

The same site lists<br>

<a href="http://www.coinminingrigs.com/amd-7950-alternatives/" target="_blank">http://www.coinminingrigs.com/amd-7950-alternatives/</a>

<div class="quote-container"><span>Quote:</span>

<div class="quote-block">

<ul class="bbcode_list"><li>AMD 7990 - Hash-rate: 1385 Kh/s | Cost: $660 | Kh/watt: 4.6266</li>

<li>AMD R9 290 – Hash-rate: 900 Kh/s | Cost: $400 | Kh/watt: 3</li>

<li>AMD R9 290x - Hash-rate: 880 Kh/s | Cost: $560 | Kh/watt: 2.416</li>

<li>AMD R9 280x – Hash-rate: 725 Kh/s | Cost: $320 | Kh/watt: 2.416</li>

<li>AMD 7970 - Hash-rate: 725 Kh/s | Cost: $350 | Kh/watt: 2.416</li>

<li>AMD R9 270 – Hash-rate: 450 Kh/s | Cost: $180 | Kh/watt: 2.25</li>

<li>For Reference: AMD 7950 - Hash-rate: 650-700 Kh/s | Cost: $300 | Kh/watt: ~3.25</li>

</ul></div>

</div>

<br>

^ 300W is a high wattage for R9 290...