How much each amd 480 need?
The specs say that it needs 500 w power supply. Do AMD 480 need 500 w power supply or just 100 w power supply each? If I have 6 AMD 480 how much power supply would I need? What about disk? Do you use SSD or HD?
Ram? is 4GB of CPU ram enough?
No 480 needs just above 150W / card, 470 is 120W i guess, I m not sure pls check. But a 1200W Gold/Platinum should be good for 470 if you mining Zcash. Eth is more power hungry.
The RAM doesnt matter, 4 GB is enough. I run a system at even 2, and it does fine.
HDD, again you just need to run the OS, if you running Windows just get a 16 GB Flash, the cheapest option. A linux can even run on even 8GB.
When mining at full speed at stock settings, an RX 480 can consume upto 200W, and an RX 470 can consume 160W. If you are going to go the Windows route, and underclock/undervolt your cards, then target consumption of 120W per card with tweaks. If you are going to go with linux, unless you get a custom ROM made by someone else, your cards will consume 150W so plan accordingly. It is recommended to have a 20% power capacity buffer on the power supply, so for a system consuming 1000W, get a 1200W PSU.
Also, RAM does matter, go for 4GB as that is a good price performance balance, the smaller your system ram is the more the paging file is used, and it results in frequent swaps and stale shares sometimes.
As for the HDD, if you are using a plug and play OS like EthOS or SimpleMiningOS, then get a 16gb SSD. If you are using Windows, get a 64GB SSD minimum as you need to allocate 16GB to paging file which you can not do on a 32GB SSD.