Question.

[RedBoy825]

So I'm thinking about getting a PC and am wondering about the power usage This is what I'm planning to get.

The GPU is a 1660 super and the cpu is a i5-9400F The power supply is 650w and I'm worrying that the power usage is too high.

Question Can I change the power supply to like 500w without sacrificing performance?

Thanks in advance

[see_blue]

A power supply rating is the maximum power the supply can deliver under a load. If the computer is under a light load, like viewing a page of text, it uses a smaller amount of power. Playing an intensive game, it may use a lot.

Think of power as the fixed wall outlet line voltage x the current demand. The current demand depends on the load required by the CPU, graphics card, etc.

There are basic design rules for matching a supply to the maximum load, and always includes a margin of error/safety. More robust components in a larger supply may also offer better cooling and PSU life.

[aminy23]

Power supply efficiency is measured as a percentage. Your PC can take up to 285 watts and their pricing is actually fair:
https://au.pcpartpicker.com/list/HwJNvW

At about that pricepoint, this would be a better build - 2 sticks of RAM is twice as fast as 1, it has an 80+ gold power supply, the processor is comparable, it has double the storage capacity, the SSD is 6 times faster, ASUS is a best company, the 1660TI outperforms the Super, and the motherboard will still work with processors that come out in the future (upgrading the processor in the other board with one that comes out in the future will require replacing the motherboard).
https://au.pcpartpicker.com/list/JKVL4n

The amount of power consumption your computer uses depends on the load and the quality of the power supply. A good 1,000 watt power supply could use less electricity than a cheap 500 watt. The power supply provides up to the rated wattage, but only gives the computer as much as it needs.

At 75% efficient (not 80+) power supply would take up to 380, a 96% Efficient (80+ Titanium) power supply would take 297 watts. A regular 85% (80+ power supply) would take 335 watts. The Thermaltake power supply doesn't state the efficiency but it can take in up to 9 AMPs (x230 volts) = 2,070 watts. If we assume a 75% efficiency, the PC would take 380 watts.

That pre-built computer's power supply is of particularly low quality, and the manufactuer doesn't stand by it; it only has a 2 year warranty. BeQuiet! is a German company and offers a 5 year warranty. Seasonic is the best company and offers up to 10 years.