Do good power cords have to be stiff?

I get that 12-14 awg should be enough wire for most components, but when I plugged in my 650 wpc monos using the 7 awg WE PCs it was one of the few times  I perceived that cables went beyond simply making a difference to making a definite improvement.  The 7ga cables are 6 runs of 10ga wire into each Furutech FI-11 connector, 2 runs each for pos, neg, and ground.  The 10ga version are more flexible and certainly big enough to handle any audio related load, but for some reason it seems the bigger 7ga cables sound even better on my big amps.

a great power cable that is very flexible: e.g., VH AUDIO Airsine.

The new ifi powercords nova and supanova are very flexibel...

In regard to having a power cord of heavy gauge (in the vicinity of 10, more or less), how many amps (or watts, probably easier to add up or check) do folks stereo systems require from the mains?

My own modest setup (Class A tube amp is the biggest draw card) I’m at less than 500 watts.

At 120 V, that’s a tad over 0.4 amps.

At 240 V, about 0.2 amps.

Off topic, I know, but kinda related.

+1 Pokey77, (Audio Envy)