Stick with the reference design just don't run the fan at more than 50% 24/7. Pretty much any other design is just going to dump the heat from the card back into the case and your temps will rise.

Another nice option that is in between cased and caseless are what are known as "Tech benches". They are basically open-air but fully rigged up cases. One example I've been looking at would be:

http://www.amazon.com/MYOPENPC-Transparent-Acrylic-Station-motherboards/dp/B004TZ56GU/ref=sr_1_13?ie=UTF8&m=A3Q4NSDXS8U7OP&s=generic&qid=1306788458&sr=1-13

I'm still trying to work out which ones would best fit the most cards though.

Just a note, you can't fit 4 double slot video cards into an antec 1200, let alone 5. Nor would you be able to fit 5 cards on the motherboard anyway, you'd need an extender for the 5th pci-E slot. That motherboard is kind of pricey for what you plan on doing, I'm not totally sure I understand whether you are building a second computer for gaming or plan on using this motherboard/cpu, but an AMD sempron will bottleneck the crap out of 6970s, so you won't be able to game on it anyway.

The only cases capable of doing 4 cards are ones with 8+ expansion slots. The only case I know capable of doing 5 cards for under $300 is the Rosewill THOR.

EDIT: Also worth noting that you will be hard pressed to find any 5850s these days. Amazon has been out of stock for about a month and there's no real reason to believe they will get any more anytime soon. Your best bet is to buy used cards or else you will have to go skinny with 5830s, another reason why it might be better to go with 2 cheaper motherboards that can utilize PCI-E x1 slots with extenders.

EDIT #2: The antec quattro is an incredible waste of money. You will likely be able to run 4x 5850s on a quality 750Watt power supply (maybe even less but let's play it safe). You can pick up a quality one of those for about half the price.

EDIT: My only comment on your build specifically would be whether or not you really want to get a Full Tower Case.

Ive got the MSI 890fxa-gd70 as my miner board... Im using 4 slots of the 5, they're double slot cards, so you're going to have to be creative... Also I dont know if its just my board, but in a 3 card configuration, I cant get the middle card to work.Im using the Sapphire 5850s as well, just fyi.

Its configured:
Card
fan
space
Card
fan
space
Card
fan

I couldnt figure it out, but every time I tried that I saw 3 devices in device manager that were 5850s, but only 2 in catalyst/display settings. It wouldnt allow me to extend the display to enable the middle card. I did have dummy plugs, and with 4 cards in the system It works well, but this is without using the black pci-e slot. Like I said it might only be my board, but check to make sure it's able to be utilized before you dive in. 4 cards run really hot when they're all in their respective slots, so be prepared for that. My cards run 300 mhash/s each, and they run between 80 (coolest card) up to 90C (hottest card).

U don't need dummy adapters for Linux Rigs. U do however need one on ur 2nd GPU on ur gaming/mining rig if u're not using dual monitor like me

I'm not sure how much power. I think I've read somewhere when Overclock the 5850 draws around 200 W. But recently I read you could run 4 of them off a 850 W. I'm not sure how much does the MOBO+CPU draws either. So I'm going with 1000W~1200W if 5x5850.

You don't need xFire to mine. Specify different miners to each GPU just like you said.

And with regards to the casing I think it'll be better to just go with no casing if you're intending to go 5xGPU since heat is going to be a real problem. Take a look at the "Show off your mining rigs" thread somewhere, you'll get an idea about casing, placement and etc.

I took the liberty to link to (see in quote) newegg to give a rough estimate of the prices, your insurance and additional investments

1000W PSU - $195 + $80 + $270 + $160 + $12 + RAM for your gaming rig = $717 + RAM
1200W PSU - + $120 = $837 + RAM

Balance from insurance should be close to $800~$1000, enough to get 4~5 GPU example (2x6970+2x5850)-(2x320)+(2x150)=$960
All these are just from ur insurance. You'd still need to buy a Sempron 140 ($38) for your mining rig, a 2/4 GB Thumbdrive ($6)(Linux) + MOBO for your gaming rig + PSU ($70) for your gaming rig [optional + HDD + OS if you need] (If you got more than 6 GPU then get PCIe extender

(PSU and MOBO assume 2x6970 xFire, 4 RAM slots for option and Cheapest Investment since if anything fails you could swap the GD70 for ur gaming rig)

This config gives you
1 Dedicated Mining Rig @ 4x5850 = 1.3~1.4 Ghash/s
1 Gaming/Dedicated Rig @ 2x6970 = 800 Mhash/s
Total = 2.1~2.2 Ghash/s

Insurance Cover $1,800
Additional Investment ($38+$6+$70[+HDD+OS]) = $114

This should be all you need. Just tweak a little to your liking. I forgot US still sells 1GB RAM and changed the 2GB to 1GB. Remember the PCIe Extender if you get 5 GPU from ur Insurance

EDIT: I forgot you wanted i7 in that case you can't use GD70 for ur gaming rig. Reconsider some of the config. This is to give you an idea.

With the $1800 at your disposal, it's probably best to splurge it all on good GPU's then.
Then make a dedicated mining machine with those good GPU's like grue suggested.
That will get you the most bang/buck as far as mining is concerned.

If the issue is with the insurance, try to get more GPU from the insurance and then use cash to buy the MOBO of ur choice
GD70 is what one of my rigs is using. It's got 5 PCIe slots.


Consider this option.
 - GD70 (5 PCIe slot)
 - 1000W/1200 PSU (support 5x5850)
 - CPU of your choice
 - HDD of ur choice (If theres a need)
 - Casing of ur choice
 - RAM (2 GB + What u want to use)
 - a few other GPU from the balance of $1,800

Piece together a dedicated mining rig using the GD70+Sempron 140 [Purchase ur own], 2 GB RAM, PSU & GPU + Ubuntu/Linux on Thumbdrive (4 GB) [For 5 GPU get 2 PCIe Extender for $9]

As for your own computer. U still have Casing, CPU of ur choice, RAM, HDD & GPU (Assuming you got 3 or more from the insurance). All you need to buy is MOBO and PSU.

You'll get at least 2.5 Ghash/s with a working computer of ur liking + dedicated rig (naked or cheap casing). (total around 5~7 GPU) With a bit more investment.

don't buy that expensive motherboard. just get a cheap one, and use risers/extenders to utilize all the pci-e x1 slots. Also, you're wasting money with your i7, just get a AMD motherboard + cheapest CPU.

Everything i said above only applies to a dedicated miner, if you're using this for gaming, this build looks decent.

How does this insurance work?
You don't get to keep the full $1800?

From what I've read that MSI board should handle quad crossfire at x8 speeds.