You are technically right, but why would you buy a video card that needs more power to be able to reach its full potential and then have the only thing from preventing your PC from trying to use more power (and blowing your PSU/Board/etc) being your 'guess' than the game you are playing won't make it use too much.
One thing you need to consider, is power supplies wear out over time, which impacts its efficiency, so the max load is reduced. Even if something works now, it might not in 2 years.
Another thing, is some PSUs, either don't come with any PCI-E power connectors or don't come with enough of them to power some cards.
__________________
"Wake up, Luigi! The only time plumbers sleep on the job is when we're working by the hour."
|