PSU getting close to its limit? - upgrade?

So my PSU is the Corsair CX500M and right now says that i'll be using 425 with the upgrades comign up. should I be concerned or is it alright?

You'll have more than enough Wattage. Those wattage calculators usually overshoot the required amount of watts..

Most systems only require 500-550W.

Correction, most companies tell you most systems need 500-550W, when really, most systems need 350 to 380W.

Just click my name and see what i am running on 500w's ;)

If I can add to this, the rated wattage is not the thing to go on.  What you want is a power supply that can deliver the needed current, without creating too much heat, without creating too much noise, and with low ripple and a few other desirable characteristics.

The "600 Watts" is just a label, and if you buy based on the label it's a lot like buying coffee by what's on the label.


You know what I was trying to say, Brennan. You know I don't go by on-the-box suggestions

If I can add to that, amperage is no better than wattage for rating the draw. You know that ATX standard operates on +12V, +5V, and +3.3V, so going by current, or by wattage, you're representing the same thing.

Ripple and load line regulation are the most important, by far, after capability (wattage). Efficiency comes last.

600W is a label in what way? It is labeling that it is capable of delivering 600W at ATX standard compliance for ripple and load line regulation at ATX standard amperage, but that is a very clear label, which would be like labeling the name of the farmer, the type of soil, and roasting methods of the coffee on the side of your cup.

i'm always clicking your name cooperman (;

Call me crazy, but I do not like using 80-90% of my rated spec. I like to guy power supplies that have been tested by someone who knows what they are doing (I only buy stuff rated by Jonny Guru) so the basic stats are good, and I like to be in the area with the best efficiency (50-75%). Many bronz/silver PSUs can hit gold efficiency in that range. 

So if you said you had a platinum-rated 500W, I would say fine (or gold), but personally, I would go buy something that has a buy rating from Jonny Guru's website. 

My objection to focusing only on the total Watt rating, is that "600W" doesn't tell you the capability on 12V, and it doesn't tell you at what temperature it was rated.

So a good "550W" could have more useful capability (for a gaming machine) than a bad "600W".

I don't think you'll find anyone here who would expect a US$40 500 Watt rated power supply to deliver 500 Watts sustained.

500 Watts actual use would be an FX8350, plus three 7870 graphics cards.


Garry this is what I do too.  I want to emphasize for others that estimating the expected sustained use under load (i.e. while playing a game) is a great starting place.  Unfortunately GPU card sellers aren't giving numbers but you can often find them in reviews.  Intel and AMD now give "TDP", thermal design power, numbers that act as guidance for sustained power draw.

Instantaneous power draw of the CPU may rise above the TDP number for a "short time".  The heat sink and the PSU can both handle these short excursions.

Normally you take your expected total sustained power draw (in Watts or Amps), and check it against what's available on 12V for the power supply.  My power supply shows 38 Amps (rated) on 12V, that's 456 Watts.

My system needs about 200 Watts of power sustained, at load.  That's not even 50% of the rated capacity (456 Watts), so my power supply is more than I need.  As Garry says normally one would aim for 50-75% so you utilize the efficiency that the PSU can provide, saving power and reducing heat.


as i see it they try to get you to buy a bigger PSU as a lot of PSUs cant handle their max rated draw for an extended amount of time.

Power supplies derate as they get hotter.  So a 600W rated at 30*C PSU turns into somewhere around 450W at 50*C.

This is why we want efficient PSUs and is why we run them at loads where they achieve their maximum efficiency.

The other factor is that we need our power on the 12V rail(s), and some PSUs deliver significantly less than their total power on the 12V rail(s).