Alright. But I need just 6 for now. Looking for ones in stock at amazon. What are differences between 470 and 570? is 570 better? So I can decide clearer. I heard theres problem running 6 570s? is this true?
570 has a slightly better updated chip but overall the same.
In terms of mining, the 470 will be better because the 570 is plagued with driver issues right now.
I got a 6x 570 mining rig going but it took me forever (Countless hours) to get it working. Not worth the headache unless you know what you are doing.
Go with 470's if you can, or take a stab at 570's if you want a challenge at the cost of possibly losing a lot of mining time trying to figure it out.
There is no special miner buying stores (To the public) for GPU's. You just have to make due with whats available at the time and source it from different PC stores and websites.
Everything is pretty jacked up in price right now though. Unless you really want to deal with the challenge, I would just buy coins.
Calculating the costs/time/headaches/generated heat/downtime/constant monitoring of all my rigs and what they have generated versus just buying and holding coins, the latter would have been the better choice.
Mining down time costs a lot of money through lost profits.
EDIT: Also, the PROVANTAGE cards mentioned a few posts up are blower style (Single fan). The disadvantage of these cards are that they have a single fan so they are noisy and also don't push around as much fan as dual fan GPU's.
I have 2 480's that pump out a lot of heat and I will NEVER buy reference cards again. Maybe if you can get an optimal setup where there is an air conditioned room for intake and the exhaust hangs outside, but noise is also an issue.