Recommend you get the following:
PSU: LEPA G1600 - 1600 Watt power supply
GPU: MSI R9 280X <- You can overclock easier with MSI afterburner.
Now, regarding the build itself:
I'm planning to work with R9 280x cards. I'll start off with 2 cards, and eventually build it up to 6 cards in the rig. Regarding this, I have a few questions:
Someone suggested that I split this between 2 rigs, so as to not keep all my eggs in one basket. I definitely understand the wisdom in this; however, knowing the fact that a computer alone will cost me as much as roughly 1.5 GPUs or 2 PSUs, would you suggest that I go for two rigs or one?
I recommend get a most powerful PSU, then you can run 6 GPUs in one rig. LEPA G1600 can power 6 GPUs.
How much power will I need to run 6 cards eventually? The highest available PSU in the market is 1200W. I don't think this will be enough. So eventually, I'm going to have to add a secondary PSU anyways. Keeping this in mind, what should be the rating of my PSUs? 2x 860W or 2x 1000W or 2x 1200W ? Note that I will try to under-volt the cards, but I don't want to rely on this.
Is Corsair better or Seasonic better for PSUs ?
Does the Platinum/Gold make that much of a difference? I'm less concerned about the power draw off the wall, and more concerned about the safety of my hardware.
You can run 6 using LEPA G1600. Platinum Rating is better than Gold.
I was planning to use ASRock 970 Extreme 4 as the MoBo, but I read on a thread that it only supports up to 5 GPUs. Which MoBo can I use for 6 cards if I decide to go for the one rig option?
Related to this question, the ASRock 970 Extreme 4 is an older board, if I'm not mistaken, and its availability is dicey. Which MoBo is everyone using these days for their rigs?
Get this mobo --> MSI Z77A-GD65 Motherboard (Intel Core i3/i5/i7/Pentium/Celeron, Intel Z77, ATX, RAID, Gigabit LAN, Socket LGA1155)
You can have up to 7 GPUs using this one. This is the one I am using.
You will need Intel Celeron, i3, i5 or i7. I am using i7, because I am also mining CPU crypto such as Quark, Primecoin and Protoshare.
I'm planning to use Linux on the system, since its meant to be a headless mining rig. So MSI Afterburner won't work.
I'd love to get the PSU that you recommended (LEPA G1600), however, its not available in my country. But since you said that a 1600W PSU will be enough, would you recommend going with 2x 860W Platinum PSUs? And would you recommend Seasonic or Corsair?
I looked into the motherboard you recommended (MSI Z77A-GD65). It looks good. The specs do say that its compatible with Celeron processsors. Since I don't plan to do any CPU mining, I don't mind going for a cheap processor. Will the board be compatible with one of the older celeron processors? (Intel G2010)
Good, Somewhere you could save your price in PSU and you need to add price of a cooler as I noticed that in india its too hot so you must think about cooling. Other is good
Thanks for your reply. I'm just planning to put a table fan for the cooling. Its going to be an open rig, and I don't think any CPU fan can ever match the power of a table fan. :-P