Can you clarify? Even if you down clock the card to 300W, why would running it at load not consume 4x300W?

Inference is often like 200-250w without card clocked down. Then the other cards are like 20w-50w. 4 cards, 1 card is active at once. To get the full 350watt, you need to run parallel inference on the card with multiple users. So if I was using it as a server card and have 10 active users/processes then I might max out the active card. For example, I have a rig with 10 MI50 cards, I believe they are 250w each. Yet I rarely see pass 200w on the active card, they idle at about 20w, so that's 180w + 200w = around 380-400w on full load.

Think of the max watt like a car's max horsepower, a car might make 350HP, it doesn't mean it stays making 350HP all day long, there's a curve to it. At the low end it might be making 170HP and you will need to floor the gas pedal to get to that 350hp. Same with these GPUs. Most people will calculate the gas mileage by finding how much gas a car consumers at it's peak and say, oh, 6mpg when it's making 350hp so with your 20gallon thank, you have a range of 120miles. Which obviously isn't true.