I believe you are both wrong. If you go back and look at the specs again, the boost speed you get in reality out of the box is whats called the "game clock".
You'll also notice that the game clock is much lower than the maximum clocks - with some tweaks and better cooling I believe you will be able to get the card to sustain it's peak clocks.
Navi clocks now function a bit like Nvidias - just adding better cooling to your gpu gets you significant extra performance
Take a look at the 50th edition specs.
Average game clock of 1830mhz - maximum peak of 1980mhz.
This card will hit 1980mhz as soon as it comes under load, and then as the tempretures go up it drops down to 1830mhz+- and sits there.
So with water cooling it should sustain 1980mhz and thats before trying to overclock.
If my theory is correct, putting the 5700xt under water should by itself get you an extra 150mhz and that's before overclocking