A newer card ties into the system more than the past.
An older card uses less cpu.
This changed for better acpi, and integration.
the old cards are like war heros.
It is an oddity in pc evolution, in fact, it is the only one I can think of. Some of them even had built in hardware programmable roms for firewalls and all kinds of stuff. large clocks, etc etc.Today, one would write a firmware hub, integrated on the mobo, and used by cpu. I like the old cards. I kept one for a 633 mhz. ZERO cpu interference...just had to make sure the "irqs" are good.
I remember the history of the newer cards unfolding, it left alot of old pros upset....