People keep asking me about what to do for their first rig etc. so I'm going to outline it quickly here and make it easy for everyone.

I recommended non-powered (regular) x16 --> x16 extenders and three cards per board.  I've run rigs like this for months on end with no problems (no motherboards frying etc)

Stuff needed: (intel build)
3x pcie x16 motherboard eg http://www.newegg.ca/Product/Product.aspx?Item=N82E16813157295
celeron cpu eg http://www.newegg.ca/Product/Product.aspx?Item=N82E16819116409
8 gb ddr3 ram (2x 4gb) eg http://www.newegg.ca/Product/Product.aspx?Item=N82E16820104262
1 sata hdd eg http://www.newegg.ca/Product/Product.aspx?Item=N82E16822136591
3x non powered x16 extenders from ebay eg http://www.ebay.com/itm/New-PCI-E-Express-x16-Extender-Flexible-Ribbon-Cable-/281070938954?pt=LH_DefaultDomain_0&hash=item4171222b4a
1x wifi adapter (any, usually usb) if needed
gold or platinum 850w psu eg http://www.newegg.ca/Product/Product.aspx?Item=N82E16817139011
3x 7950s (MSI and Sapphire are some of the few non-volt locked ones right now) http://www.newegg.ca/Product/Product.aspx?Item=N82E16814127667

Build is the same for amd, just use a board with 3x pcie x16 slots and a cheap cpu

Then, buy this from home depot:
2x plastic crates
small wood or metal screws that are pointed, about 1.5-2.0 cm long and are small enough to go in the GPU plate holes
2 ft ruler shaped flat piece of steel (they sell this in 4 ft I think, you need to cut them in half with a hack saw)
vinyl stick on cushions http://www.homedepot.ca/product/1-2-clear-vinyl-pads-surface-gard/948073
--> $10 for a case

Put the vinyl cushions on the bottom of one of the crates.  Put the motherboard on top of the cushions.
Put the PSU in the other crate.  Add RAM/CPU.  Hook up the PSU to everything.
Insert the extenders and plug in the hard drive.
Put the cards on, screwing them into the inner lip of the plastic crate and bracing them with the flat piece of metal you bought as a cross member towards the end of the card.
Plug the card into the extender and connect remaining power bits.
Turn rig on by shorting the power pins on the motherboard with a screwdriver, then set the motherboard to turn on as soon as power is given to it ("Wake on power" option in BIOS).
Install Windows (use a USB drive or connect a SATA DVD Drive temporarily), mine (I use guiminer-scrypt).

This is what it looks like:


Rig power consumption at 1.8 MH/s is ~750 watts in summer or ~650 watts in winter.

Great thread. Is there any scripts that we need to install? Or is it pretty much,

1. Construct LTC miner
2. Install windows
3. Start mining LTC

thanks taco looks great .It's what i got so far was looking to add one more card..What do you think.

It really doesn't matter.  With this build the PSU is in another crate and you can tie up loose cables with cables ties.

Cooling.

Yes, modularity and cooling.  Also these are quicker to build, I can get about 10-20 units up and running in a day if I clone the HDDs.  The crates themselves only cost $2-3.

Box fan(s) moves far more CFM than almost any case. Good job, tacotime!

^I suggest cleaning the drivers (I used AMD cleanup utility after using catalyst uninstaller). If you are downgrading your opencl SDK/AMD APP, you may have to remove those specific files from your windows (or whatever) directory. The locations should be in the APP installation notes.


Although it could just be a bad reaper config.

Don't you think 850w is too small for 3 7950s? i have a 750w for my 2 7950 setup

A good 850w psu can power 4 7950's on an energy efficient cpu setup. I've been running my corsair AX-850 golds like this for a while and have a seasonic gold doing the same.

Hey men that is cool how many hashs do you do with all those gpus