That's not true, fortunately. You do need a router with a beefy CPU, though. With SQM (CAKE) enabled, my WRT1900acs router (1.6GHz dual-core) can handle my 500

That's not true, fortunately. You do need a router with a beefy CPU, though. With SQM (CAKE) enabled, my WRT1900acs router (1.6GHz dual-core) can handle my 500/100 Mbps FTTH connection just fine, with plenty of CPU to spare. From my calculations it probably doesn't quite have enough CPU to sustain 1 Gbps, should I ever upgrade to that. But the router itself is a few years old now, so that's not really surprising.