In all honesty, now is not a good time to be purchasing hardware, especially considering you're doing so for a long-term investment. By the time you open, the hardware you would have purchased for your grand opening would be obsolete. NVIDIA Pascal (Q4 2015/Q1 2016) is reported to
more than double the performance of NVIDIA Maxwell. You should consider pushing back the plans until June of 2016 and hold off on purchasing any capital. In doing so, you will literally have the most advanced and high-tech cyber cafe in your entire city because you would have anticipated such changes in technology, thus having the best hardware available.
What am I implying? You will spend $50k~ on hardware either way, however, waiting until next year will give you twice the effective usefulness and lifespan than that of current generation hardware. This means you're litterally getting more "bang for your buck."
Anyway, here are some recommendations:
- You want to purchase an NVIDIA GPU. AMD GPU's may be cheaper, but they're hotter, have worse driver support, and AMD products are not known for their longevity. An NVIDIA GPU will save you time and money, long-term, considering you most likely won't be upgrading hardware every year.
- You need to purchase a GPU with more than 2GB's of VRAM. Again, a cyber cafe is a long-term investment. Next generation games are starting to have recommendations of 4GB or more, and are utilizing more than 2GB's today. Don't skimp out on hardware to save a few dollars here and there. It will come back around and bite you right in the ass.
- A quad-core CPU (e.g. 4690k) is a definite plus. It has been shown that next generation games are demanding more from processors. You don't want to have an entire cyber cafe full of computers unable to handle new games.
- Memory is important. 8GB's is more than enough for a gaming machine, and I think this amount is ideal. What frequency should you purchase? At least 1600MHz. In the USA, 2400MHz memory is only $20 more than 1600MHz. So, I'd recommend that if you can find a good deal.
- A Z97 motherboard is also a good idea. It is more "future" proof than most others. Definitely recommend going with something modern.
NVIDIA's next generation Pascal GPU Architecture - NVIDIA Blogs