How do you define "swapping?" Even on Intel Macs, the memory statistics don't map the way one might expect. Be careful when making assumptions about what those metrics actually mean.

I mean at that point (13 GB memory used), the "Swap used" is at several hundred megabytes.

And if I more apps (or browser tabs), the "Swap used" keeps increasing, and the "memory pressure" graph switches color from green to yellow.

The color of that graph is the indicator I'm using to know that I should close my browser tabs :p