So I'm gonna get about 5 XFX 390's soon with the purpose of mining Ethereum. I'm getting them at a decent price, hence my motive for getting into mining.

My biggest issue at present is getting the right PSU. I'm planning on using:

Mobo: Asrock H97 anniversary
CPU: Intel G1820
RAM: 8GB
Others: Powered risers - https://www.amazon.com/Fixable-Adapter-Flexible-Extension-Connector/dp/B00IMYODGS?ie=UTF8&ref_=cm_cr_arp_d_product_top

Now, for the PSU, I was planning on getting an EVGA 1200W Supernova (Platinum): https://www.amazon.com/EVGA-SuperNOVA-PLATINUM-Crossfire-220-P2-1200-X1/dp/B00KYK1CKI

But I've come to realise that it may be quite insufficient to support 5 cards. 

My question thus, is whether or not the above-mentioned PSU would be insufficient for 5 cards. If it is, would it be possible to use 2x 750w PSU's (Gold) instead? - http://www.newegg.com/Product/Product.aspx?Item=N82E16817438017