Originally Posted by OrSpeeder
As I said, 370W FROM THE WALL
of course it is full system wattage, I never saw "per-part" measurement of power from the wall.
And the 380X is not old, it is the most recent consumer (not "Pro") AMD GPU (at least until the 480 actually launches). And I mentioned it, because I bought one recently.
And I did took power efficiency in account, I said reviewer machines with GOOD PSU, saw 370W watts from the wall, meaning a budget (ie: bronze/white and non-80 cert) PSU probably would draw something like 400 to 500W from the wall.
The 380X in particular is a sort of "mainstream" card, thus if you have a higher end card, you can imagine a 500 or 600W PSU might be risky (ie: it will still work, but close to the PSU limits).
Or if you have multiple 380X for some reason.
Or if you use all the computing power of your machine (doing scientific computation, simulations, CAD, mining, etc...).
Also, if you look in the 80-plus rules, and ATX specs, they expect the PSU to behave at its best on 50% (ie: on 80-plus the 50% need to be more efficient than all other load levels for example), so maybe a good way to decide on a PSU might be calculate your average power usage on your most important loads, and then use that as "50%" level (thus if you calculate that in your most important tasks you will use 400W, it might be good idea to buy a 800W PSU).
Of course, all of that I am just conjecturing, so feel free to ignore me, I am just explaining why maybe people like high-end PSU.