When I was mining with a desktop of latest generation 6th to be precise , a core i3 processor I did a maximum of 9-10Sol/s. The processor consumes very low amount of watt and is only 51 watt still I don't know where to send my ZEC after mining it.

Going up a little bit, you are saying only 1 R9 390 gets approximately 150 Sol/s and it's intriguing.

If I build a mining rig with 4 GPU- R9 390 I get 600 Sol/s and that's it 0.04 Zec per hour or almost 1 zcash per day. My cost of energy (through some friends is cheaper than my country) and I think 4 R9 390 don't need more than 1200-1400 watt.

Sounds like is quite some profitable or isn't it ?