[SOLVED] PSU - UPS wattage issue

karthik.gems

Reputable
Nov 5, 2018
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So my PSU (650W) died a few days ago and its warranty is already expired. Other parts are working fine.
I am trying to get a Corsair RMx model or Nzxt psu, but I am only able to find 750W models in our market. Also the price difference between 650W and 750W is also minimal here.

But the issue is, I have a UPS which is 1000 VA, which means, it should support around 600W. Till now I was using 650W PSU but there was never an issue with power backup and it always worked fine.

Now if I use a 750W psu, will it still work fine?
As per outervision power supply calculator, my pc takes 500W maximum.

I want to also understand if a psu provides such 750W, does it mean it needs UPS or other hardware that can support 750W, or does it depend only on what the pc is actually drawing?
 
Solution
So my PSU (650W) died a few days ago and its warranty is already expired. Other parts are working fine.
I am trying to get a Corsair RMx model or Nzxt psu, but I am only able to find 750W models in our market. Also the price difference between 650W and 750W is also minimal here.

But the issue is, I have a UPS which is 1000 VA, which means, it should support around 600W. Till now I was using 650W PSU but there was never an issue with power backup and it always worked fine.

Now if I use a 750W psu, will it still work fine?
As per outervision power supply calculator, my pc takes 500W maximum.

I want to also understand if a psu provides such 750W, does it mean it needs UPS or other hardware that can support 750W, or does it depend...

kanewolf

Titan
Moderator
So my PSU (650W) died a few days ago and its warranty is already expired. Other parts are working fine.
I am trying to get a Corsair RMx model or Nzxt psu, but I am only able to find 750W models in our market. Also the price difference between 650W and 750W is also minimal here.

But the issue is, I have a UPS which is 1000 VA, which means, it should support around 600W. Till now I was using 650W PSU but there was never an issue with power backup and it always worked fine.

Now if I use a 750W psu, will it still work fine?
As per outervision power supply calculator, my pc takes 500W maximum.

I want to also understand if a psu provides such 750W, does it mean it needs UPS or other hardware that can support 750W, or does it depend only on what the pc is actually drawing?
The maximum wattage a power supply can deliver and the actual usage are two very different things. It is the equivalent of the speedometer in your car being able to register 120MPH. You have to replace the speedometer and the new one has a maximum 160MPH. Did the top speed of the car change? No.
Changing the maximum wattage power supply will not change the actual usage of the PC.
 

karthik.gems

Reputable
Nov 5, 2018
86
4
4,535
The maximum wattage a power supply can deliver and the actual usage are two very different things. It is the equivalent of the speedometer in your car being able to register 120MPH. You have to replace the speedometer and the new one has a maximum 160MPH. Did the top speed of the car change? No.
Changing the maximum wattage power supply will not change the actual usage of the PC.

So this UPS should work fine even with 750W or even 1000W psu right? Considering pc takes only 500W max.
 
So my PSU (650W) died a few days ago and its warranty is already expired. Other parts are working fine.
I am trying to get a Corsair RMx model or Nzxt psu, but I am only able to find 750W models in our market. Also the price difference between 650W and 750W is also minimal here.

But the issue is, I have a UPS which is 1000 VA, which means, it should support around 600W. Till now I was using 650W PSU but there was never an issue with power backup and it always worked fine.

Now if I use a 750W psu, will it still work fine?
As per outervision power supply calculator, my pc takes 500W maximum.

I want to also understand if a psu provides such 750W, does it mean it needs UPS or other hardware that can support 750W, or does it depend only on what the pc is actually drawing?
The 1000VA rating is how much power the battery can deliver once main power is cut. It will be able to deliver about 600W of power then for a few minutes.

A 750W PSU means that it can deliver any amount of power up to a maximum 750W. Therefore your other components will be fine.
 
Solution
A psu will only draw the power demanded of it, regardless of the max capability.
Overprovisioning is usually a good idea to allow for future upgrades.
As in your case, the price difference is often minimal.
In the event that you need more on battery run time, or you think you are close to being overloaded, reconsider what is connected to the ups.
For example, a second monitor may not be essential in the event of a power failure.
If you are using an APC ups, install the powerchute app and you can monitor what power you are currently using.
Other vendors may have something similar.