What is disadvantage of having a bigger psu than your system need?
 
I heard a lot from people that "no matter how big your psu is, it will only consume what it needs". Is this true?
 
I currently have a 1000w P2 psu... based on "EVGA powersupply buyer's guide". My psu should still be efficient even at 20% load. It would still manage to give me 90% efficiency.
 
Are any of this true? Please help
 
Currently my system specs are:
i7 4790k
EVGA Z97
EVGA GTX 780 Classified
EVGA P2 1000W
Corsair Carbide 540
Corsair H105
Corsair 480GB XT SSD
Western Digital Blue 500gb 1x
Western Digital Black 750GB
 
In the next month or two I would be replacing my gtx 780 Classified with Gtx 1080 Ti FT3.
 
 
Please help.
 
Thank You!

Hoggle
It shouldn't cause a big issue but you have a few things to consider. First off would be the cost of the PSU which in the case of already owning it becomes a moot point. If you are not using the extra power though it's a waste of money to buy a PSU to big. It will also be slightly less efficient but that shouldn't really be an issue. The positive though is as you get higher in wattage components inside the PSU normally get better so it's typically considered wise since it also helps future proof the investment in the system for things like the GPU upgrade you plan to do.
 

1. Is the evga efficiency rating true? Would I still get 90% efficiency even at 20% load? (20% of 1000 = 200)?
2.Would my electric bill raise significantly? ($5 to $10 difference?)
3. BTW, I also contacted evga tech support and they told me that my psu will still use 1000w even my system only run at 250-350W?
 
Thank you!
 
 
 

Jaycee1994
1. Is the evga efficiency rating true? Would I still get 90% efficiency even at 20% load? (20% of 1000 = 200)?
2.Would my electric bill raise significantly? ($5 to $10 difference?)
3. BTW, I also contacted evga tech support and they told me that my psu will still use 1000w even my system only run at 250-350W?
 
Thank you!

 
1) Efficiency ratings depend on load. If you buy a 1000w PSU and put a 200w load on it, you are outside its best power efficiency curve (would tend to be 60-80% load).
2) JonnyGuru saw a difference of 2% efficiency with the EVGA p2 1000w so it is not a big deal, it won't even reach $5 assuming you ran the PC 24/7. 2% on a 500w load is 10 watts.
3) I think you misunderstood them, the PSU only uses as much power as it needs.

Answer to your title question --> weight
 
Rule of thumb;  When planning a build, the load should equal around 80% of the planned PSU rated output or less
 
So, if you buy one GPU but are planning on going with two with your next upgrade -- buy the correct PSU to meet your plan
 
 

Thank you all for your replies! I will give an update once I finish my upgrade.
 

bcavnaugh

Jaycee1994
What are you using your Computer For?
I will use my computer mostly for gaming, recording gameplay, video/photo editing, watching movies and surfing the internet.
 
How Many Monitors do you have?
I only have 1 monitor
ASUS VG248QE Black 24" 
 
I don't know how to calculate their wattage... Are you referring to my monitor or psu?
 
What is your Computer Doing when you are not using it?
My computer would always be off if im not using it. unless im downloading or uploading something overnight, which is very rare.
 
My computer will never stay on for 24/7, I will most play games games for 6-7 hours then shut off.

For the Most Part This was based on "2.Would my electric bill raise significantly? ($5 to $10 difference?)")
Some members us LED/LCD TV's for Monitors and they do run warm and the older the more wattage is used.
My LED TV is runs at 250 Watts and my LED Monitor only runs at 189 Watts and some of my Older LCD Monitors run at 230 Watts.

I will keep that in mind thank you!

 
A little more is always better. Don't skimp when it comes to the PSU. (Ram also).