Swords and plate

[Lucian]

Another post brought up a fact I knew about but have long forgotten.

Swords can't pierce plate armor.

In reality, never on a cutting attack,
Thrusting, with 2 hands you might only pierce
A few centimeters.

In gurps any mook with about 14 15 st
Can many a swing attack and reasonably best
6 DR with a sword. Using basic set numbers here.

Does anyone have house rules that address these issues?
Obviously, this concerns more realistic games.

I was thinking maybe plate has an armor multiplier of 2 vs swords, unless a successful attack is made by targeting chinks