R9 290 with Rosewill 600W PSU

GTX 270? Are you talking about R9 270 or GTX 770?

It's a dual rail PSU. Are those two PCI express connectors carry different rails or it's attached to the same cable?

R9 290 requires 31 Amps on the 12v rail. Each rail of your PSU provide 19A. So if can combined it'll be somewhat fine. But overall I wouldn't trust that PSU.
 
My bad, I'm talking about the R9 290 and the GTX 970. (I'll edit that typo.)

So you're saying the Rosewill can do it? I don't mind upgrading it in the near future if it'll be fine for a few months. I don't plan on heavily overclocking the graphics card, and certainly not right away.

The Rosewill has been a damn fine PSU. It cost me somewhere between 60 and 80 bones when I got it and it hasn't given me crap yet. I've had problems with cruddy PSUs (to the tune of $20-30 PSUs causing terrible explosive-type issues and wrecking components), but reading all this about 80+ and certifications is all stuff that is new to me.
 


You have been lucky with this Rosewill. It is not a good unit and I would not trust it.

Strongly suggest you replace it with a quality unit.

Its actual usable wattage is only 456W (assuming the labelled specs are accurate), and that is over 2 12v rails, which would mean most of that goes to waste anyway.

 
I'm sorry, but I'm a power supply noob, apparently. What does that actually mean? Why is it not a good unit? I'm certain that I purchased it because it had a great reputation at the time, even though it's aging. What is the deal with the rails?

I also run my power thru a UPS before it hits my PSU.
 


Well the most obvious indicator of it being a dodgy unit is how its amperage is distributed. Its just really bad design to make almost half of the power output be on the 3.3v and 5v rails.

From a few amateur forum test the 3.3v and 5v rails are FAR out of ATX specification and fluctuate A LOT.
Since I can not verify this I will not bother posting sources or take their word for i, BUT as a general rule of thumb, if the unit is not reviewed and approved by reliable sources then DO NOT trust it unless proven otherwise.

Note : Rosewill units had some of the worst reputations before they started improving about 4 years ago.



 
Multi rail means, The AMPs are divided into sections. Your PSU is a dual Rail PSU Which carry 19A on each rails. R9 290 requires 31A to perform well. So unless you are providing both rails to this GPU, it'll not get the AMPs it requires. Most dual rail Power supplys mark their rail with patterns on the yellow wire.
I think you better read this.

http://www.tomshardware.com/charts/power-supplies,26.html
 
Huh. This is all good info, thanks, and I'll peruse some of those resources (are you pointing me to one article specifically? Because I see quite a few...)

If my current PSU has two six pin connectors already, are those the two separate rails? (Or perhaps those are called the PCI Express connectors?) Or are the rails akin to the MAJOR "veins" that split off into all of the different connectors? (The latter doesn't really make sense to me.)