First off, you're either nuts or just full of crap that you are gonna buy $8000 for a mining rig. Presumably you are a newbie.. Sure you can get a motherboard, pci risers, and probably pick out some decent cards (although you'd likely mess that up, so I'd buy 2 at time and learn about rom modification and all the different tweeks involved in getting a rig not only running efficiently but stable. Cooling is critical, so your environment is important. Are you gonna run winbl0ze which has better drivers or ethos which is far more stable but requires some technical skill to run...

I would take that $8000 and just invest it in your coins of choice. It's alot less work and at the end of the day, has a better chance at success than building a rig. Rig maintenance is alot of work. The golden days I think are pretty much behind us too, so how long do you plan to be in this game where you are basically breaking even or making less than min wage? It's a distinct possibility.

I have a 6 GPU rig that I run but that's b/c I have deep knowledge and it's already setup. I would NOT start from scratch today. HELL NO. In fact after this season- I'm likely out of the game. It's been fun and profitable but it's just not worth the time investment anymore.