Gday boys,
i've been working on a rig and here are the specs so far: 4x HD7950, 8gb Corsair DDR3 1600mhz ram, Intel Celeron G3900, 8 basic cheap easily replacable fans to keep things nice and cool and 4 usb gpu risers. What i cant decide on is the PSU and motherboard. Also does the Celeron need a cpu fan too? I chose the gpus because i had one of these lying around from my old pc, the ram is from the old pc too.
Now for the software, im using nicehash miner on my main pc (GTX 970, FX8350). Im kind of new to this so i really dont know if thats a good choice.

Okay guys so heres the thing, I'm currently using my main pc and Nicehash miner just to try this out, i've been reading a lot but there still are some unanswered questions that i have.
I've recently been thinking about making a mining rig, now the thing is i dont know if i should buy 3 HD7950s, because i have one lying around so i would have 4 gpus, or just buy one powerful card used only for mining 24/7. The 7950s would cost me around 350$ so that isn't a problem. Should i use my main computer and just take out the gpu (im currently running a GTX 970) and buy a new psu (i have a Corsair CX600) or buy a whole new setup (cpu, ram, etc.).
If i buy a whole new setup the parts are mostly going to be cheap, excluding the PSU and motherboard. That means a single core intel cpu, 8 gigs of 1600 mhz ddr3 ram (i have that lying around too). What motherboard would you recommend?
Another question i have, are these cards even a good choice? I chose them mainly because i have an old 7950 lying around and they are cheap.
Now if i bought these cards, how the fuck am i going to fit them onto one motherboard?
Lets not consider electricity in terms of profitability, since i pay a fixed amount for electricity with my rent. I consulted this with my landlord and he said that he doesnt care.
Just for your information this wont be my main income, its just that i wanted to try something different, im expecting a yearly return of 1100$ including the ROI of the gpus (not the other components tho).