What are power supplies with multiple rails for?

[Seth L]

Title states exactly what I'm looking for. More or less, explain what rails are and what benefits/draw backs they give/have. I know nearly nothing about PSU's other than what wattage I should need.
Always strayed away from PSU's with multiple rails because I didn't understand what they do, so you'll have to dumb it down for me so I understand.

 

[shag00]

Simplistically they split the power similar to the different power points in your house so that 1 outlet is not used by all your appliances. Multi rail is generally speaking very good especially for high output PSUs. The only real draw back is they cost more.

 

[Seth L]

Ah. So if I'm drawing a lot of wattage for, say, my GPU and CPU, they should be on a separate rail?
I'm seriously dumb on this concept, lol.

 

[shag00]

Don't sweat it, basically yes.

 

[Seth L]

Awesome.
Thank you.

 

[westom]

Ah. So if I'm drawing a lot of wattage for, say, my GPU and CPU, they should be on a separate rail?

Once amps get too large, then cheaper is to provide two separate power supplies. Meanwhile computers that draw less than 200 watts and maybe 300 in a short spike are systems recommended for 600 watt supplies. Supplies are so overpowered as to be irrelevant which rail is used.

Damage can result if both rails do not maintain a similar voltage.