Well, I just discovered that on my "multi-gigabit desktop switch" (4x1Gbit, 2x2.5Gbit, 2x5Gbit, 2x10Gbit) apparently plugging a 10 *M*bit Ethernet system into a 10*G*bit port, it simply won't run it.
Psh, what happened to backward compatibility?!
Also, I can't find any speed tests that work properly on iCab 2.9.9 on Mac System 7.1.2...
Even DSL Reports old "simple" test doesn't work properly on it.