my friend wants to buy a gaming pc and rendering ,but he dosent know much about it .
so he told me and trusts me.
so help me to buy
what about these
ASUS P9X79 PRO Motherboard
Corsair Neutron GTX Series 120 GB SSD or Samsung 840 Series 120 GB SSD
Core i7-3930K Processor
Corsair Vengeance DDR3 8 GB 2133mhz or 1600 mhz
Asus NVIDIA GTX680-DC2G-4GD5 4 GB GDDR5
no idea about power supply and cooler
You're over-investing in CPU and under-investing in GPU. A 3770k should meet his needs just fine. With the money you get from that downgrade, you can give him dual 7970 or dual 670, both of which absolutely annihilate a single 680. Also, definitely go for the 1600 RAM. You get next to nothing from faster RAM speeds on Intel CPUs.
Does he have a general budget?
For the PSU, I would go SeaSonic, but how large a supply would vary based on the other components. If he wants a lot of overclocking and a CrossFire/SLI of high-tier cards, a 850-1000w would probably be best. If he only wants a single card, I'd take that down to a 650w.
Edit: The 1 card = 650w rule does not factor for dual-GPU cards. For those, you're going to want a bit more power.