> every technically-inclined person in the city quickly discovered that Ethernet controllers in consumer PC's can't come close to pushing gigabit Ethernet, regardless of what's printed on the box

Really? I have a chromebox (CPU is Haswell Celeron 2955U, NIC is Realtek 8168), running Windows and can hit about 950M down/833M up on dslreports speedtest when my ATT fiber is having a good day. I thought Realtek nics were considered poor, but getting to 95% of theoretical over the internet seems pretty ok to me. In a browser and going through my NAT box, plus ATT's mostly useless residential gateway.

What are good examples of junky gigabit nics that don't cut it?