I am concern about 12 rails, not P.W. total ratingIf you are going to use a 400w PSU to power a 1080ti, you're going to have a bad time.
I can tell your concern is with the 12 volt rail based on your OP and thread title, but that still doesn't change anything with running a 1080ti on a 400w power supply.I am concern about 12 rails, not P.W. total rating
For example I have a spare OCZ Stealth Xstream II OCZ 700 SXS2 700W 80 Plus. Which doesn't have enough on 12 volt rail to handle it.
Not to mention, POTENTIAL FIRE HAZARD. (Ok, if the "protections" in the PSU trigger properly, it should just "shut down". But these things are not always 100% certain.)That 10 year old+ PSU has one PCIe connector, and is not made/designed to handle a high-end card like the 1080ti. Even if you can get it to work initially by rigging it , you're either going to kill the PSU or your GPU. However, it's your stuff so......
I am concern about 12 rails, not P.W. total rating
For example I have a spare OCZ Stealth Xstream II OCZ 700 SXS2 700W 80 Plus. Which doesn't have enough on 12 volt rail to handle it.
ThanksYou have plenty of power with that 700w power supply. PCIe1 and PCIe2 are on separate rails. a 1080 Ti has two plugs. You have a total of 432w between those two rails dedicated to powering the graphics card.