Bitcoin Forum

I want to get into LTC mining or some other scrypt alt crypto mining so i was thinking id ask bitcointalk's community what they are using and what they believe to be the best

products for a nice scrypt rig. I was thinking of starting with 2-4 cards probably a 7950. But also would like recommendations on brands, as well as other hardware like good

motherboards, processors , power supply, and anything that's a necessity. price really isnt an issue im just trying to get a high hash and still a reasonable power appetite.

It would also help if you provided links too since you guys can find the best deal! Okay thanks! :D BTCBTC

Lookup zif33er (Zif) / hostedmining.com - he provides this service.

Are you looking for a parts list, or someone to build and ship you a turn-key LTC rig?

Thanks guys, sorry i guess the topic is misleading. I mean find me the parts for the best ltc mining rig.

Im able to build it myself 

All i want is the forums opinion on the best products to use

Thanks

any suggestions on best 7950?

http://www.coinminingrigs.com/

if you can afford 7950, then you should jus go h.a.m, get the 7970s, sapphire twin x oc edition, then a 1500 watt power supply gold certified. you dont need a really powerful cpu, but i'd suggest the 22nm i5 and minimum of 8gb ram, if you use reaper, get 16gb. you may want to use a custom case or crate for your build. to allow the hardware space and additional cooling. pcie risers are a good option, get powered ones. i use a ssd, i dont know if that improves performance.

I'm running 3 of these 7950's and have been getting 1,870 kh/s stable. I had them running a little over 1,900, but the rig would crash every couple days. I think these would be the better bang for your buck than 7970's by far! Especially if you can get em on sale, which they do run them on sale quite often, plus there is a $20 rebate.

GPU: http://www.newegg.com/Product/Product.aspx?Item=N82E16814202030

Mobo: http://www.newegg.com/Product/Product.aspx?Item=N82E16813157262

CPU: http://www.newegg.com/Product/Product.aspx?Item=N82E16819103888

RAM: http://www.newegg.com/Product/Product.aspx?Item=N82E16820231314

I had a 1,000w PSU laying around that I used.

You can't go wrong following this guide:

http://www.cryptobadger.com/build-your-own-litecoin-mining-rig/

I have 3 of these rigs. The MSI 7950 will hit ~670 Kh/sec per GPU while undervolted, so each rig will net you ~2000 Kh/sec for about $1400 (less if you sell the game vouchers that come with the GPUs), all while consuming only ~720 watts of power total.

Gigabyte 7950s from Amazon.com. I am running 2 right now until I get my powered risers, each card is pushing 700KH/s scrypt. I don't understand why people say to get 7970s for $100 more new when you can get your 7950s to run 715KH/s stable with the correct parameters.

wow thanks for the feedback guys!

so this is what i got so far. tell me if you can find a better price


motherB- http://www.newegg.com/Product/Product.aspx?Item=N82E16813157262

CPU- http://www.newegg.com/Product/Product.aspx?Item=N82E1681910388

GPU- HELP ME CHOOSE either sapphire - http://www.amazon.com/dp/B0098HW1HG/ref=as_li_ss_til?tag=onsimobicomps-20&camp=0&creative=0&linkCode=as4&creativeASIN=B0098HW1HG&adid=1W7W8M2XM1A5AMFRJHN8         orr MSI - http://www.amazon.com/exec/obidos/ASIN/B007NG3WR2/cptbr-20

RAM- (is 4gs good?) http://www.amazon.com/exec/obidos/ASIN/B002RPCLH6/cptbr-20

ill get some risers

last thing i need is a good power supply! give me your suggestions!

Thanks for your help!

I'm surprised so many people are recommending 7950s. You can build a 5 gpu rig with 7850s that will do 1.9-2 mh/s for around $1100. With good sales, it would be even less and you get more game codes to sell.

Here is what I built - pretty happy with it so far.

https://bitcointalk.org/index.php?topic=209433.msg2193589#msg2193589

7850 vs 7950.  wattage per kHash.  7950s are cheaper the longer you run them vs the 7850s.  How fast that savings is returned is determined by the cost of your electricity service.  Also increased density.  I can get more GPUs in one box for total wattage than I can with 7850s.

http://www.coinminingrigs.com/

Mining Rig Build Guide – 4x GPU Mining Rig
75 Replies
Home-built Litecoin or Bitcoin mining rigs are a great way to invest in the new digital currencies, while avoiding some of the risk involved in purchasing the coins outright. By building a mining rig, you invest in off-the-shelf litecoin mining hardware that can later be re-sold (sometimes at a profit), if gpu mining become unprofitable in the future. Today’s Mining Rig Tutorial will show you how to assemble a fairly easy to build milk crate mining rig, capable of 3GH/s for bitcoin mining or 2,800KH/s for litecoin mining. I have built several of these rigs for myself and friends. Build time should be no more than 2 hrs for a machine that, as of the time of this writing, will mint you anywhere between $15-$25 USD worth of crypto-currency every day. As always, your mileage may vary.

Mining Hardware Build List

Power Supply – $250 Seasonic X-1250 80PLUS Gold Certified Power Supply Unit
Motherboard – $99 –  ASRock MB-970EX4 Socket AM3+/ AMD 970/ AMD (best motherboard for mining at the moment, and in stock at Amazon as of this article).
Graphics Cards (GPU) – $1,200 to $1,600 I use four of the Sapphire Radeon HD 7970 at $400/ea or four of the Sapphire Radeon 7950 at $320/ea in each rig. This one with a stock cooler works also, and can be had for only $280 (after mail in rebate). One of the Amazon reviews for the $280 card, shows specific settings for Litecoin mining which is helpful. To answer the 7970 (~$420) vs 7950 (~$320) question, basically, the 7970 gets roughly 100-150 more Mh/s or Kh/s than the 7950 for higher hashing density per rig (see bitcoin mining hardware comparison and litecoin mining hardware comparison). I couldn’t decide either and ended up buying both types for my rigs. Either card will work great in this mining rig build.
CPU – $40 - AMD Sempron 145 Processor (get the cheapest you can find since this has no bearing on mining, but is a necessary component of course)
RAM  - $55  –  8 GB Corsair DDR3 RAM (Litecoin mining can be fairly memory intensive, especially if you are using GUI Miner with Reaper, which is one of the easiest to configure, so 8GB is about right for a 4x GPU mining rig).
1x to 16x Powered Riser Cables - $18 –  (2x $9) PCI Express 1X to 16X Slot Flexible Extension Cable (to connect 2 cards to both 1x slots on motherboard and allow spacing between cards for heat dissipation – powered risers are easier on your motherboard) If these are sold out, ask around on the bitcoin or litecoin forums. They tend to be hard to find.
Powered 16x to 16x Riser Cables – $30 – (2x $15) PCI Express 16X to 16X Slot Flexible Extension Cable (to connect 2 cards to both 16x slots on motherboard – using a powered riser cable will put less strain on your motherboard) If these are sold out, ask around on the bitcoin or litecoin forums. They tend to be hard to find.
Hard Drive –  $50  -  500 GB SATA laptop drive (alternatively you could boot Linux from a USB drive or get a small, but very fast Solid State Drive for around $40)
Case - $6 - Plastic Milk Crate (you might be able to pick one of these up at an office supply store for less)
Extra Cooling  -  $30  -  Box Fan (best cooling for a mining rig, pushes all that hot air away from the rig)
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).
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)
TOTAL COST TO BUILD A LITECOIN MINING RIG:
~$2,200 for a 2,800 Kh/s Custom Litecoin Mining Rig (based on 4x Sapphire Radeon HD 7970)
~$1,800 for a 2,200 Kh/s Custom Litecoin Mining Rig (based on 4x  Sapphire Radeon 7950)

 

Daily Litecoin Profit in USD:
~$20/day (on 4x Sapphire Radeon HD 7970 at current difficulty / exchange rate @0.10/kwh)
~$15/day (on 4x  Sapphire Radeon 7950 at current difficulty / exchange rate @0.10/kwh)

 

Putting it all Together – Assembling your Litecoin Mining Rig

Unpackage everything
Install processor and RAM on motherboard
Plug in all riser cables
Place motherboard in plastic crate
Plug in SATA hard drive
Connect all GPUs to riser cables and fasten them to plastic crate evenly spaced out for maximum heat dissipation
Plug in all power supply connections
Connect mouse, monitor and keyboard and an internet connection (I used a USB WiFi adapter)
Check all connections once more
Fire it up! Install the OS if needed. Install Graphics card drivers. Install mining software. Make sure fans are doing their job. Fire up the mining software, tweak for maximum hasrate and let ‘er run!
This entry was posted in GPU Mining Rigs, Mining Rig Guides and tagged 7970, Bitcoin Mining, coin mining, cpu, Feathercoin, Feathercoin Mining, gpu mining, Litecoin Mining, mining, Mining Rig, Motherboard for Mining, psu on April 23, 2013.


Read more: http://www.coinminingrigs.com/#ixzz2U3FNiVBx

Mining Hardware List
Essentially, a Litecoin or Bitcoin 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.

Power Supply – $115  -  Corsair 850 Watt Bronze Rated PSU. A high efficiency, gold-rated power supply uses less power, but if your electricity is under 0.15/Kwh it may not be worth the extra $. I like modular PSU’s for ease of assembly.
Motherboard – $85 – ASRock 970 EXTREME4 AM3+ AMD 970 Motherboard (this motherboard has two of the 16x PCI-e slots for your two videocards spaced far enough apart for airflow that PCI-e riser cables are optional.
GPUs – $640 (2x $320)  -  Sapphire Radeon 7950   -  I use these 7950′s and have overclocked them to mine Litecoin at 600+ Kh/s each and Bitcoin at over 600 Mh/s each. Though I haven’t used it myself, this Gigabyte 7950 has been recommended by other mining rig builders (it can get up to 700Kh/s with a firmware flash according to folks on the Litecoin forums). Another recommended card is the $299 Sapphire 7950 (with a stock cooler, which basically sucks air in the side of the card and shoots it out the back). Check out the one Amazon review on that last card, detailing how to configure cgminer for this specific GPU. For specific configuration details be sure to read this litecoin mining hardware comparison.
CPU – $35 - AMD Sempron 145 Processor (get the cheapest you can find since this has no bearing on mining, but is a necessary component of course)

The 7950 is the best GPU for Litecoin Mining.
RAM  - $30  – 4GB Kingston DDR3 RAM (Litecoin mining can be fairly memory intensive, especially if you are using GUI Miner with Reaper, which is one of the easiest to configure, so 4GB is a good amount to have for a 2x GPU mining rig).
Hard Drive –  $40  -  32GB Solid State Drive or boot Linux from a fast USB thumb drive)
Case (optional) – $6 - Plastic Milk Crate (you might be able to pick one of these up at your local office supply store for less)
Power Switch  -  $6  – A basic Motherboard Power Switch does the trick, making it easier to start up your mining rig.
Extra Cooling  -  $30  -  Box Fan (best cooling for a mining rig, pushes all that hot air away from the rig)
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).
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)
 
Upgrading Your Budget Litecoin Mining Rig
Minus the optional cost of the operating system and mouse/monitor/keyboard for setup (I assume you already own this trio), our rig easily slides under the $1,000 limit we set for ourselves. One of the nice features of this litecoin mining rig, thanks to the motherboard’s additional PCI-e slots, is the ability to upgrade it to a 4x GPU rig (effectively doubling your hash rate). You would simply need to purchase two more Radeon 7950 graphics cards, four PCI-e riser cables (one 1x to 16x and three 16x to 16x, to space the cards out for airflow), and one additional cheaper 650 watt power supply to provide power to the extra cards to make this a 2,400 Kh/s rig. To connect your two PSU’s safely, I’d recommend an Add2PSU Multiple PSU Adapter. You can use this adapter for bigger builds as well. I’ve seen folks connect two 750 Watt PSU’s with one to power a 6 GPU mining rig.
 
Putting it all Together – Assembling your Budget Litecoin Mining Rig
Un-package everything (be sure to keep original packaging for future re-sale or warranty work)
Install the Sempron 145 CPU and RAM on the motherboard (the processor comes with a good heatsink and fan assembly; it’s a question I am often asked).
Plug in the hard drive or optionally a USB thumb drive.
Insert the 7950 graphics cards in the 16x PCI-e slots (big blue tabbed slots)
Plug in all power supply connections
Place motherboard in plastic milk crate (This is optional, as some folks prefer to set the motherboard up on a table or utility shelf, like this one, without any case. The milk crate comes in handy if you plan to put the graphics cards on riser cables.)
Connect mouse/monitor/keyboard and an internet connection (You can use a USB WiFi adapter, however in my experience, a hard wired ethernet cable connection to your modem/router will have fewer ‘stale shares’ when mining Litecoin.)
Check all connections once more
Start up your rig! Install the operating system, latest graphics card drivers, and  mining software. Make sure the fans are doing their job. Start the mining software, tweak for maximumhash rates and mine some Litecoin!


Read more: http://www.coinminingrigs.com/#ixzz2U3Admb1S

7950s do have increased density, but I'm not so sure about the power draw. Let's compare 3 7950s at 650 kh/s and 5 7850s at 390 kh/s. I don't have a kill a watt meter, so I have to use video card reviews for power consumption figures.

Using these two reviews and the maximum card power consumption,
http://www.techpowerup.com/reviews/Powercolor/HD_7850_PCS_Plus/26.html
http://www.techpowerup.com/reviews/Sapphire/HD_7950_Vapor-X/26.html

the 7950 uses 200w and the 7850 uses 120w. Both sets of cards use 600w. While mining at overclocked settings, the actual power consumption is probably higher, but they should maintain the same ratio with the 7850 using ~60% of the power of a 7950.

Even if you assume the 7850 rig uses 100w more than the 7950 rig, let's calculate how much you save on electricity. At a rate of $.10 per kw/h, you would save $87.6 over an entire year.

So basically moot.

update

so this is what i got so far. tell me if you can find a better price


mobo- http://www.newegg.com/Product/Product.aspx?Item=N82E16813157262 $100

CPU- http://www.newegg.com/Product/Product.aspx?Item=N82E16819103888 $38

GPU-  sapphire 7950 - http://www.amazon.com/dp/B0098HW1HG/ref=as_li_ss_til?tag=onsimobicomps-20&camp=0&creative=0&linkCode=as4&creativeASIN=B0098HW1HG&adid=1W7W8M2XM1A5AMFRJHN8     $310x4

RAM-  16g ripjaw  http://www.newegg.com/Product/Product.aspx?Item=N82E16820231568  $130

PSU- http://www.amazon.com/dp/B00607JLWU/ref=as_li_ss_til?tag=onsimobicomps-20&camp=0&creative=0&linkCode=as4&creativeASIN=B00607JLWU&adid=1JN8VG129ZC6781AD7MA $255

HD- http://www.amazon.com/dp/B009SKB5HA/ref=as_li_ss_til?tag=onsimobicomps-20&camp=0&creative=0&linkCode=as4&creativeASIN=B009SKB5HA&adid=1Z8N15NZ79NDYHWT3NY0 $50

all i need is the risers. which should i go with??? 1x? 16x? and powered??

thanks

total so far $1808

Depends on what the board has. If you have 4 16x slots you only need 16x to 16x risers. If it has 1x slots you need 1x to 16x risers for those slots. Get powered just so you save peace of mind of your rig potentially burning out/up/etc.

No one ever mentions this, but it's important, especially if you have no choice but to have your rigs in your living area (and not, say, in a basement).  A lot of the 7950s' labeled above and older 7970s' fans can be loud.  Like industrial vacuum cleaner loud.  So keep that in mind when people say 7950s have 'bigger bang for the buck'.  It's a bit literal given how loud they can be.  I personally went H.A.M. with 7970s (Sapphire vapor-x) and I get 740kh on them (6 of them).  I also tried the Gigabyte 7970 and I get 750kh on them (2) but one failed withing 24 hours and they generally run hotter than the Vapor-x.  Plus, the vent is vertical, whereas the vent on the vapor-x is horizontal, which is the preferred vent flow for closed case.  No one mentions these little details, but since the Gigabyte has vertical vent (both out of the top and bottom), if you don't have proper spacing and you mix cards, then the Gigabyte will vent hot air right into the fan of its neighboring gpu, gimping its performance.  This cannot happen for the Vapor-x.  But they are both pretty quiet, even with fans at more than 90%.  I then purchased 3 Sapphire 7950s to see just what all the fuss was about.  And I must say, 650kh for $300 is quite good.  But they consume more electricity than my 7970s because I have powertune set to 20, else they won't be stable.  And my biggest gripe, those fans sound exactly like a vacuum cleaner on high in the next room.  I live in an apartment suite, so I have no choice, until I relocate later this year.  Just some food for thought...

Personally:
AMD Sempron 145 Sargas (2.8GHz, single core)
AsRock 970 Extreme3 or Asus M5A97 (Newegg currently has a sale on the M5A97: http://www.newegg.com/Product/Product.aspx?Item=N82E16813131872 (http://www.newegg.com/Product/Product.aspx?Item=N82E16813131872))
4GB DDR3 (I like G.Skill, personal preference. Corsair RAM is great too!)
750W EVGA Supernova (Nice modular design, runs well, quiet (cause that's really important xD), comes with a nice warranty, good price, I personally go with Bronze usually)
250GB Western Digital of Seasonic hard drive, just get one for $50 that has 4+ stars. Sometimes 500GB is $3 more, so I go with that one. :)
MSi Twin Frozr3 7950 (Works good, bios is right, had 14 and only one had a small fan issue)
If you need a case, the Blackhawk works pretty well for me after a few minor modifications, namely flipping the direction of the side panel fan, really easy to do
If you need to install using optical media, get a cheap $15-$25 Samsung SATA optical

Cheers!

No need for 16GB RAM unless you're planning on using it as a gaming machine too. Looking good though. I say go all out and do a crate build out. Make sure to buy a box fan!

https://imageshack.us/a/img5/873/optimg20130521203242.jpg
https://imageshack.us/a/img585/7457/optimg20130521203205.jpg
https://imageshack.us/a/img825/6161/optimg20130521203224.jpg

what is compatible with the sapphire 7950 to a ASRock 970?

CPU: AMD X2 cheapest
Mobo: MSI 990FXA-GD65
Ram: 4GB ram
HDD: simple mechanical HDD (no usb stick, will kill performance till you slowly grow mad)
GPU: 4x Sapphire HD7970 (11197-03-40G)
PSU: Seasonic X-1250
4x PCI-e 1x to 16x riser cable
Some iron wire for PCI-e presence mod
Linux.

This is how I built my rigs, they eat 1200W from the socket and provide with 3000kh/s each.

whats the right pci risers for a ASRock 970?

update

so this is what i got so far. tell me if you can find a better price


mobo- http://www.newegg.com/Product/Product.aspx?Item=N82E16813157262 $100

CPU- http://www.newegg.com/Product/Product.aspx?Item=N82E16819103888 $38

GPU-  sapphire 7950 - http://www.amazon.com/dp/B0098HW1HG/ref=as_li_ss_til?tag=onsimobicomps-20&camp=0&creative=0&linkCode=as4&creativeASIN=B0098HW1HG&adid=1W7W8M2XM1A5AMFRJHN8     $310x4

RAM-  16g ripjaw  http://www.newegg.com/Product/Product.aspx?Item=N82E16820231568  $130

PSU- http://www.amazon.com/dp/B00607JLWU/ref=as_li_ss_til?tag=onsimobicomps-20&camp=0&creative=0&linkCode=as4&creativeASIN=B00607JLWU&adid=1JN8VG129ZC6781AD7MA $255

HD- http://www.amazon.com/dp/B009SKB5HA/ref=as_li_ss_til?tag=onsimobicomps-20&camp=0&creative=0&linkCode=as4&creativeASIN=B009SKB5HA&adid=1Z8N15NZ79NDYHWT3NY0 $50

all i need is the risers. which should i go with??? 1x? 16x? and powered??

thanks

total so far $1808


should i splurge on better cpu for cpu only mining like yac? (not that i want to mine yac just for future alt coins)

7950's prove to be more profitable. The extra electricity, plus the extra $100 per card, is not worth the little bit of extra hashing power. Not only that, 7970's are notoriously harder to get the settings right. I have the 3 fan Gigabyte 7950, and I get 620 KH/sec, at stock speeds.

That mobo you picked, that's only got 2X PCIE16 slots, is that enough? I've also read in places too, that 3 GPU's per board is better, for cooling purposes, and, so you don't have to fuck around with powered riser cables.

Also, I read that 8 GB Ram should be plenty

thanks that was helpful

what motherboard you recommend then?

Further research indicated that that board is the best for mining right now, it's the 1X16, and 16X16 powered riser cables, make the difference. 4 GPU's are better. I'm also in the process of designing a rig. I found this website very helpful;

[link] http://www.coinminingrigs.com/ [/link]

Can you please back this up with data?

The data I have is that I draw 1243W from the socket with 4x 7970 @ 750kh/s - significantly faster than 7950. With 90% PSU efficiency, this means 1118W at the PSU side --> minus ~160W for processor, motherboard, HDD and peripherals, 958 W for just the cards --> 239W per card. The 160 was based on the fact that the idle system draws 220W, and data suggests the 7970's use 15W per card @ idle.

Now, I hear the 7950's draw about 200W per card (can you confirm?), at 620 KH/s

So, this means:

7950 ---> 620/200 = ~ 3.1 kh/W
7970 ---> 750/239 = ~ 3.14 kh/W

And this makes sense as it's practically the same board, but at higher clocks. So as the output per watt is practically the same (give or take 5% in my assumptions), I see no reason why not to put the top cards in your system :/

You can undervolt a 7950, still get ~650 KH/Sec, at 40-50W less, bringing it down to ~150W per card.
Also, the initial investment is ~$400 more, for 4 7970's.

As I said can you back this up with data rather than throwing random numbers in the air? How did you get to the values of 40~50W and the 150W per card? Also suddenly 650 kh/s?

Also one can undervolt a 7970 too :/


To get the same hashing power out of 7950's, you're eventually going to need more motherboards, processors, RAM, etc. Also, even though the investment is greater, the return of investment stays the same period as you have a higher hashing power. The 7970 is 21% faster, and the investment is 25% larger. These numbers are in the same ballpark and therefore I still do not see why one would not buy the most hashing power per motherboard :/

http://www.reddit.com/r/litecoinmining/comments/1ddhie/undervolt_overclock_and_cgminer_settings_for_2x/

There's 1 guy here, who is running 3x7950's, undervolted, and is drawing 730W from the wall, which would encompass the entire rig.

I've seen many posts, on this forum, and others, with problems getting the full hashing power, from a 7970. They are finnicky. From what I can tell, 7950's are the prefered card for mining. But it's all personal preference, and depends on things like, how much $$ you have to spend.

I only have 7950's, so, I can't speak from experience, as to which is actually better, just refering to data I've collected.

https://bitcointalk.org/index.php?topic=203946.0

Now, some people also say that 7970's have a higher resale value, which is true, up to a point. Once the next gen cards come out, the resale value of all 7xxxx cards plumment. When I tried to sell my 5870, after buying my first 7950, I had a hell of a time.

I have 3 Sapphire 7970 OC running stable at 720Kh/s, total rig draw only 750W at the wall!

Was looking into 7950 since everyone is raving about it, but now that I see they only get 630-650Kh/s and drawing 730W, plus someone mentioned horrible vacuum noise level (I live in apartment too without a garage or basement), 7970 seems to be the best bet!

The Milk Crate route with a tiny twist.. just set the cards at a 45 degree angle to help cooling and put a 15$ box fan on the top. Cards stay about 75 C or less.

Also powered with two 750w PS as that is cheaper than one 1200w PS.. using the add2psu.com module.

Also this draws ~1200 watts at the wall, and does ~2.4Mh/s. I can probably improve this some, just have not had the time.

http://markofthescorpion.com/thumbs/rig05tplp.jpg (http://markofthescorpion.com/?v=rig05tplp.jpg) http://markofthescorpion.com/thumbs/rig05side.jpg (http://markofthescorpion.com/?v=rig05side.jpg)

Does it make much sense to build a dedicated GPU rig at this point in time?  I calculated a simple payoff of 5 months (which sounds good) for a rig that I'd build, but with BTC difficulty increasing at 10%/week it looks like it might never pay itself off.

Thoughts?

Also while I am posting, is a 650W gold PS enough to power a rig with 2 7950's?  (my current 7950 appears to draw ~200W).  I think the extra 200W should be enough to power the rest of the PC components...

7950s atleast in my experience pull about 300W each.. so it would be close with 2 7950s + CPU and HD.. might be ok if you went the linux route and used a USB to boot.

BTW i would not mine BTC, just will never keep up with the FPGs or ASIC miners. Mine LTC/or some other scrypt, then convert it to BTC.

I started with 4 rigs of 2 GPUs in each. Spent $4000 on the whole setup. 1st month made $1700, 2nd month I am working towards a goal of about $1500. So I project the 3rd month I will start making money on this project of mine.

I was using BTC to calculate the worst case scenario.  Of course I will mine whatever is most profitable.  I began mining BTC/altcoins with a 7950 on April 9th and have just reached b/e on my investment.  I don't expect the payoff to be nearly as quick next time...

Yes I have 2 rigs exactly like this. 650W + 2 x Sapphire 7950s but no hard drive just USB boot. Powertune at +20 and they are very, stable each rig doing 1250 kh/s for LTC mining. Should be even less power draw for BTC mining.

this add2psu.com module sounds interesting - i made a mistake of getting 2 psus to power 4 cards in a single rig and eventually split them up into 2 rigs when i couldn't get it to work - i never factored in that each card can draw upto 75W from the mobo  - i'm assuming using 2 psus with this adapter worked out for you. any issues? would you recommend it?

is there a special cable or adapter i need for the power supply to reach all 4 cards?
link?

Not if you buy the Seasonic 1250W gold 80+ it's modular(cables plug into PSU and components so you dont have a lot of clutter. The PSU comes with straps to organize the wires as well. Very good setup in the PSU box. Best PSU out IMO.

That is a cool looking rig, but aren't you kind of adding 2 points of failure?

perfect thanks :)

MOBO http://www.newegg.com/Product/Product.aspx?Item=N82E16813157262

RAM http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=40739&sku=C13-5720

HDD http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=143901&sku=TSD-160AS8

4x GPU http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=7835235&sku=A271-7951

PSU http://www.amazon.com/dp/B00607JLWU/ref=as_li_ss_til?tag=onsimobicomps-20&camp=0&creative=0&linkCode=as4&creativeASIN=B00607JLWU&adid=1JN8VG129ZC6781AD7MA

CPU http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=3734679&Sku=I69-3220

Risers http://cryptosupply.com/products/powered-16x-to-16x-pci-e-riser-cable



if no one objects to my order list i will commit and buy this :)

the only thing I object to is the 7950, I have 2 and all I can think of is that I am losing 200 K/Hs than if I had 7970s, and I just ordered 2 from Amazon last night and they showed up at my door this morning before I woke up. I was impressed.

All my 7950's happy sit at 650.  One of them gets 680-690.  You just need to find your cards g-spot.