I think my internet is slow tonight :-?
Anyway..
Amiga 4000 060/50Mhz 2+16+128mb ram, mediator with 10/100 netcard and Voodoo 3000..
PC: AMD Sempron 2600+ 1,6Ghz with 512mb ram, onboard graphics card and onboard 10/100 netcard..
I can't tell much about my PC, it's just a cheap office pc.. I did not have a nice A4000 system when I bought it in 2006.
I just had standard A500/600/1200 machines back then :-P
I tried to download the same Firefox that you did.
Amiga: 2min 8sec
PC: 1min 41sec
Then I tried VICE-AROS64-2.0.tar.gz from aminet, 6,3MB..
Amiga: 43sec
PC: 49sec
This was a nice expirence for me :-D
But anyway, I usaly download with about 200kb/s, but it was slower than normal tonight :-?
Both computers are connected to the same switch.