Power supply issues or is it enough?

Alright folks, it took me a couple months but with deal scowering and advice from you guys, here it is. Please let me know if something is off or something i should exchange. 

Monitor: (3x) Samsung B300 Series S24B300EL 1920x1080 5ms GTG

Case: Corsair Carbide 400R Mid-Tower

Processor: Intel Core i7-3770K Ivy Bridge 3.5GHz (3.9GHz Turbo) 

Motherboard: Asus P8Z77-V LE Plus

RAM: (2x) 8 GB Patriot Gamer 2 Series 240-Pin DDR 3 SDRAM 1333

GPU: (2x) Gigabyte GV-R787OC-2GD Radeon HD 7870 GHz Edition

CPU Fan: Cooler Master Hyper 212 EVO

Hard Drive: (2x) SanDisk Extreme 120 GB SDSSDX=060G (1 for Boot/ 1 for Games)

Storage: (2x) Seagate Barracude 3TB 7200 RPM ST3000DM001 (1 for Media/ 1 for Others and Backup)

PSU: Antec HCG-620M 620W

Optical: SuperMulti 16X DVD RW 

 

There ya go folks. One concern is whether or not my power supply can handle it all. Before I insert the second gpu for crossfire, should i get a larger PSU? and if so. any recommendations?

crossfire support really isn't very good, so you should probably stick with a single gpu, get the sapphire or msi 7970

The GPU's are in possession already. black friday deal and a friend hooked me up with one more... Thats how i have two. So either way, ill be stuck with them. Would the power supply be enough though? 

I'm interested too.

 

I've messed around with different crossfire and sli builds on pcpartpicker to see what their estimated wattages are and they always stay somewhere around 500W (namely 660s and 7870s), but then the 7870 recommends a 550W PSU by itself...  Is there something missing from pcpartpicker's estimations?

620 watt isnt really enough to stay comfortable, definatly go for somethin higher like 750 watt

I am getting mixed responses. Some folks tell me its totally fine, others say it isnt. Is there a calculator or something that can figure it out? Hah, it just seems crazy. 

i use this to get a second opinion on the pcpartpicker wattage estimate, then i add 50-100 watts to the recommend to be even more comfortable