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Question PSU Calculation

enesdogan26

Prominent
Feb 22, 2018
11
0
510
0
When i try to calculate my PC's power consumption with OuterVision Power Supply Calculator it shows a value of 230 Watts.
But when i calculate it by hand i get this:

  • CPU(E5200):60W
  • GPU(R7 240): 30W
  • RAM(2*2GB):10W
  • HDD(Sata 7200):10W
  • Motherboard: 30W
  • 4*USB2.0 : 10W
In total i get 150W.

Which one is correct? Why there is so much diffrence between them? Btw i need to calculate it because i have a 300W power supply. And i want to upgrade.
 

PC Tailor

Distinguished
Herald
It depends on where you've gotten your values from.

The online PSU calculators will always add an error onto each component, and a % margin onto the overall wattage to account for any headroom or any components that may go above the design specification.

So if your values contain the highest recorded wattage pull in live benchmarks, then yours is probably trustworthy. Just it's a common error for people to use TDP W or Design Power Usage when doing these calculations which aren't so accurate - Either way, the online calculators will always be more generous, due to the error mentioned above, and also the last thing it would want to do, is recommend someone a power supply, for it to then not be enough.

Additionally, remember that the total W of the power supply is not what entirely powers your most power hungry components. It's the 12V rails.
So basically, I can have 2x 300W power supplies (1 good quality, and 1 cheap poor quality), one of which will be fine for my system, the other one which won't be.
The quality of your PSU is just as important as the wattage.
 

enesdogan26

Prominent
Feb 22, 2018
11
0
510
0
It depends on where you've gotten your values from.

The online PSU calculators will always add an error onto each component, and a % margin onto the overall wattage to account for any headroom or any components that may go above the design specification.

So if your values contain the highest recorded wattage pull in live benchmarks, then yours is probably trustworthy. Just it's a common error for people to use TDP W or Design Power Usage when doing these calculations which aren't so accurate - Either way, the online calculators will always be more generous, due to the error mentioned above, and also the last thing it would want to do, is recommend someone a power supply, for it to then not be enough.

Additionally, remember that the total W of the power supply is not what entirely powers your most power hungry components. It's the 12V rails.
So basically, I can have 2x 300W power supplies (1 good quality, and 1 cheap poor quality), one of which will be fine for my system, the other one which won't be.
The quality of your PSU is just as important as the wattage.
Thanks it helped a lot.
 

Darkbreeze

Titan
Moderator
A CPU upgrade of that nature is not going to represent a significant enough increase in power consumption to make enough of a difference from what you have currently to even be worried about.

Now if you were upgrading to a reasonably higher end graphics card or a much higher TDP processor, that would be a different story. In this case, you should be fine with what you have.
 
Reactions: enesdogan26

enesdogan26

Prominent
Feb 22, 2018
11
0
510
0
A CPU upgrade of that nature is not going to represent a significant enough increase in power consumption to make enough of a difference from what you have currently to even be worried about.

Now if you were upgrading to a reasonably higher end graphics card or a much higher TDP processor, that would be a different story. In this case, you should be fine with what you have.
I have a 60W cpu and i want to upgrade to an 80W cpu.
 

ConanLock

Commendable
May 22, 2019
1,128
241
1,690
141
On the side of your PSU, there should be a sticker that says how many amps it can give for each voltage. Under +12v, how many amps does it say? It might be split into +12v1 and +12v2, or one might be a +12vCPU.
 

Darkbreeze

Titan
Moderator
That is the maximum THEORETICAL TDP, and even if it were 100% accurate, that would still mean you were only using 250w on a 300w PSU, which is well within allowable tolerance.

In reality, your system is probably using more like 228w even WITH a core2quad 95w CPU. Unless there is a fundamental problem with the power supply, (faulty, known poor quality, VERY low power, etc.) in which case it should be replaced anyhow, adding an additional 20w load is a non-issue even under the worst of circumstances.
 
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