I'm planning on getting a new video card. Between these two.


If i get one of those will i need to get a new PSU? As of right now i have a 450watt PSU in my computer.

Super Dave

Both cards require a minimum of 500 watts, cranow. 


Yeah you definitely don't want to skimp on the power supply for one of those cards, I just built a new system with an MSI 7870 in it and though it uses a lot less power than my old computer, it's still requires about 460watts under load, which your power supply probably doesn't even hit 450watts anymore if it's even a year old. I would at least get a 550-600 watt psu if you want it to last you a while, and I wouldn't go cheap either, it could end up damaging your nice new video card and that's the last thing you'd want to do because it wouldn't be covered by the warranty.


SWDescent hit the nail on the head. The only thing I would add to that if you just want to go with something that will run either of those two cards then make sure you get the highest 80+ rating you can. They can get expensive but not terribly so. bronze is good but if you can get silver or gold or maybe even platinum would be better. Im sure if you look around you can find some good deals and newegg atleast once a week has a deal on a quality PSU in the 600-800W range.


Efficiency ratings are important and bronze is a good standard for a minimum but I wouldn't emphasize on that too much since it really only imapcts your electric bill in a minimal way unless you're running it full load 24/7 which most people never do. Going up in efficiency ratings can rack up the price of a PSU pretty quickly, especially in the platinum range.

Wattage is first and foremost and it' important to consider the selection of power cables and modularity for his case too

The website pcpartspicker is a great site to look around on to find exactly what you want for the best price if you don't feel like scouring through online retailers


I think the rating on it is as important. You can go buy a 1200w PSU that will work but you can also buy a high end 850w gold or platinum that could work better depending on what you are running. 

Ive seen a few systems running a high end cpu, mobo, water cooling system, and SLI 680s or 670s with a 850 gold. It really just depends on the system but the wattage is becoming less important the more manufacturers are building cost efficient equipment. As long as you have a basic knowledge of what power requirements you have so you can ballpark it and be conservative. 


Doesn't the efficiency relate to how much power it draws in to produce its listed wattage, not how efficient its output of listed wattage is? I may be wrong, but that had been my understanding.

As in a lower efficiency psu would take 550 watts to output its listed 500 for example, so the primary effect isn't the output of the PSU but effects from the draw like their impact on your electric bill and such.

That was why I was saying it's more important to make sure you have enough for a system than that it's platinum efficient, especially considering the price jumps that correlate with higher efficiency ratings. 


From what I understand about the rating is how efficiency it delivers power to components. Platinum is in the 92-95% range I think of the max wattage. A non rated PSU is around 75-80%. So if you have a higher rated PSU you don't need as much wattage because it can deliver consistently say 550-560w of a 600w PSU instead of say 75% which is 450w. Not to mention the rated PSU almost always seem to be of a higher quality build than non rated.