Just to clarify, all that's important for gpu mining is your gpu.
how much profit does that translate to depends on a triangle of factors;
the price of the coin you're mining, the difficulty/hashrate of that coin's network & the price you pay for electricity.
try www.whattomine.com to see how much you will make mining different coins.
try http://www.mininghwcomparison.com to see how different gpus perform for mining different algos!
there is a lot of information to digest but do research before jumping in!
if you have expensive electricity, beware 290x consumes a lot of energy.
there's a new generation of gpus that are much more efficient.
amd rx 480 & gtx 1080,1070 look them up see if they are available in you area yet!
whatever you're mining you will not need 16gb of ram!
my rig has 2GB but if i do it again i'd get 4GB which is mooore than enough!
the motherboard you mentioned has 4 PCIE slots which means you can have 4 GPU's attached to it for mining using risers.
(if you don't know what a riser is, google "pcie riser" or "pcie usb riser" you will find numerous useful links & decide which suites you best.)
also your motherboard would have 2 PCI slots that are utterly useless for mining.
don't waste your money, look for an MB with upto 5,6 PCIE slots & no PCI
that way you can have more GPUs on the same MB;
keep in mind mining with more than 5 GPUs on one MB is pretty technical & you will need bios mods & so on.
if you're not techie stick to 5 GPUs at most & keep it simple!
lastly you will need a powerful PSU to feed electricity to the rig.
you have to research the power consumption of different parts of your computer, calculate how many watts in total it needs & buy a psu accordingly!
Thank you guys...