Hello guys

Nice to meet you all, i'm new in this cryptocoins world.
I've been reading about trade and mining and I will try to do some mining to see if it's profitable or not.

I already have a desktop with the following specs

Power Supply: I dont know the Watts of it but I'm pretty sure that can handle 2 good GPUs
Motherboard: Intel DP965LT - The MB has one PCIe 16x and others 3 PCIe 1x (can I put 4 GPUs on my motherboard using risers ? of course depending on the Power Supply)
Memory: 4GB DDR2
HD: 500gb
Graphic card: That's the poing of it
To get start on mining to see if worth the effort and money, I'm thinking of buying the RADEON RX 470 4GB.

Can you tell me if worth the investment ?

I'm thinking about mining ethereum or zcash with this setup, do you guys think that can be profitable ? and with time if i get some goods results I will increase the numbers of graphic cards.

Thank you