650W PSU vs. 750W PSU

[mjbn1977]

Hi, I am just building a new gaming system (i7-8700k and GTX 1070). All online PSU calculators on the web tell me that I need 550W. I think it doesn't hurt to go with 650W. Newegg now has a great deal on the CORSAIR CX750M V2 (2017 Edition) for $50 after mail-in rebate. Unfortunately not for the 650W version.

What would be the downsides of using a 750W PSU in a single GPU system? I am planing moderate overclocking on CPU and GPU.

My goal are to have a PSU that is reliable and is more silent than my MSI GTX1070 Gaming while gaming.

Budget is between $50 and $80 for the PSU.

Again, hat would be the downsides of using a 750W PSU in a single GPU system (compared to a 650W PSU)?

Thanks.

 

[richiestang_78]

There is no downside to using a larger PSU, it will only ever draw the power your system is drawing however there is a curve of overall efficiency, meaning if you get a PSU larger then what you need your overall efficiency will go down.

Also all those PSU calculators are very very very generous on the needed wattage to account for junk PSUs.

This is 10 bucks more then your budget prior to a mail in rebate but its on sale right now and is a great PSU

https://www.newegg.com/Product/Product.aspx?Item=N82E16817438093&cm_re=evga_supernova_750_g3-_-17-438-093-_-Product

 

[Rdslw]

In general NOTHING. Mostly you should look at cooling and efficiency, which is BEST somewhere in mid, and cooling can be quieter on STRONGER PSU.
IMHO 650 and 750 should be same for you.
http://www.tomshardware.com/reviews/corsair-cx750m-psu,4799-4.html
Interesting parts:
it is worse than 650 in most stats, but slightly
300-550W peak efficiency is 86% and thats really good.

 

[Dark Lord of Tech]

750W would be overkill

620W , PLENTY OF POWER , Made by SEASONIC , Fully Modular for better cable management , GREAT PRICE.
PCPartPicker part list / Price breakdown by merchant

Power Supply: SeaSonic - EVO Edition 620W 80+ Bronze Certified Fully-Modular ATX Power Supply ($65.98 @ Newegg)
Total: $65.98
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2017-11-09 09:20 EST-0500

 

[mjbn1977]

Doesn't the efficency rating (bronze, gold, etc) measure efficiency at 50% load? Doesn't that mean if your system uses 400W under load, a 750W would be more efficient than a 650W? Or do you understand this whole PSU thing wrong?

I keep looking around, but it looks right now I get the better deals for 750W units. Seems like it is 750W sales week. Now I am tempted to go with a 750W even so its overkill.

Originally, I wanted to go with the Seasonic Focus Plus Gold (550 Watt). It is recommended a lot as a good value. But supposedly it gets pretty loud under higher loads.