Which is better?

When going up a hill in a car that has little or no power and is a manual, is it best to stay in 5th gear, or over drive gear, or downshift. Dumb question I know.

Downshift. In an auto you turn O/D off when you're going up a hill, so you'd want to get out of the O/D gear in a manual.

try to downshift into third and if it still lakcs power, drop it to second. and the 5th gear in manual transmissions are usually overdrive gears, or let me correct that...in any manual transmission cars the highest gear is the overdrive gear