Planned Upgrade and PSU question

[Ghost Of Anarchy]

So, recently I got looking into the power require of an R9 290 to see if it could run on my 600 Watt PSU from ATNG. (Which by the way I've never heard of.)

 

And the requirement on Newegg and other sites is 750W which people on a handful of other sites say that's to cover them from stupid people using very under powered and bad PSUs, which is understandable.

However I've seen a few people say a 290 wouldn't be fine with the PSU of that power.

 

And if you were wondering why I never researched the brand of PSU I got it's because when I bought the PC from CyberPower the option was something like "600W Certified Manufacturer" or something like that. And I just now discovered the brand. I cannot find any reviews on their model ATM-600FB and I'd rather not fry a 290 or something nicer.

 

Spec List:

Gigabyte GA-970A-DS3P - Motherboard

OEM AMD FX-6300 3.5 GHz - CPU (Non-OC'd)

XFX R9 280 - GPU (Non-OC'd) with a Corsair Hydro 100i

2x 4GB Corsair Vengence 1866 MHz DDR3 - RAM

Toshiba 7200 RPM 3.5" 1TB HDD

ATNG 600W PSU

Corsair Air 540 Case (Moving parts into, current case is a mid-tower)

 

Also, if anyone can recommend some upgrades for anything I'd love to hear em'. At the time of buying the PC I didn't have a stable flow of cash, now I do so upgrades are wanted. And I'd like to have my rig be able to have a stable 60 FPS on 1080p, as it stands it might be because the games I play are poorly optimized for AMD/in general like FFXIV.

[Octavialicious]

An R9-290 would be fine with like 550w. Maybe even less, this should do http://www.newegg.com/Product/Product.aspx?Item=N82E16817438014&cm_re=600w-_-17-438-014-_-Product It's a trustworthy psu with a good sale, and even a mail in rebate

[Ghost Of Anarchy]

Hmm.. I might get one of those eventually. But, it's good to know a 290 will be fine on my current 600W. I'm just worried about the manufacturer is all, then again if it's ran my 280 this long I'm sure it's fine.