800 dollar budget pc

Hey guys this is my first build and i wanted to know several things. 

1.can i overclock with this mobo?

2.is this psu enough to add another gpu and crossfire them?

3.over all thoughts comments on build and suggestions?

Now for the build http://pcpartpicker.com/p/tZJ3WZ and since i am using the haf 912 i willk be using a http://www.amazon.com/Anker%C2%AE-Front-Panel-Connector-Adapter/dp/B00J4EZE4U/ref=sr_1_2?ie=UTF8&qid=1411616836&sr=8-2&keywords=anker+3.5

Want something else that's top-notch and can last a long time with upgradability? Here you go: http://pcpartpicker.com/p/DP7NsY

1. yes, pretty sure

2. probably. there are quite a few PSU calculators out there if you want to check. here's one http://www.coolermaster.outervision.com/

3. what led you to that brand of video card? I've never heard of them so i can't speak to their quality, but if your unfamiliar with the quality and picked because it is cheaper, I'd be sure to look up reviews for the brand. It's never a bad idea to go with the well known brands like sapphire, gigabyte, asus, msi, etc

don't forget to price peripherals into your budget if you don't already have them. those can really add up and blow the budget 

1. Yes

2. Probably, but that power supply isn't very good.  Voltage regulation is not very good and there is a decent amount of ripple.   Also, if you want to overclock I suggest getting a higher wattage power supply  Here are a couple I would recommend:

http://pcpartpicker.com/part/evga-power-supply-110b20850v1

http://pcpartpicker.com/part/antec-power-supply-hcg850m

http://pcpartpicker.com/part/seasonic-power-supply-ss850am

http://pcpartpicker.com/part/corsair-power-supply-rm850

http://pcpartpicker.com/part/xfx-power-supply-p1850bnlg9

3.  Looks good otherwise.