HD 5770 CF is power/amp sufficient for my psu ?

[naveenk]

I currently have a XFX HD5770 with a Huntkey Green power 550w psu... I am planning on buying an another HD 5770/6770.

I did enough research and psu power calculations to find 550w is enough for crossfire 5770. But I am not very familiar with the amps and rails and i dont understand them and cud someone explain them ? So could you please tell me if my PSU has enough amps/rails for an another HD 5770 ? And its says here http://www.hardwaresecrets.com/article/754 in the review of my psu that its SLi and Crossfire compatible. (My other specs are: Core i5-750, Asus p7p55d mobo, 2x 2GB DDR3, 1x 7200rpm 1tb seagate hdd, 1x DVD-RW, 1xPCI-NIC card)
PSU specs are :

 

[simon12]

I would not chance it because of this review http://www.hardwaresecrets.com/article/Huntkey-Green-Star-550-W-LW-6550SG-Power-Supply-Review/668/10 which states your PSU explodes if it gets close to the maximum power.