Not sure of your numbers exactally but if you mean
12 Megabit which is what the providers go by upsteam is a buttload for a home network.

It is 12288 kilobits/1536 kilobytes/1.5 megabytes per second

8Mbit or megabit I'm guessing again is
8192 kilobits/1024 kilobytes/1 megabytes per second

My dsl 3megbit connection download / 768k upload
should be 384 kilobytes per second download
and 96 kilobytes per second upload.

Actual is more like 350 kilobytes down and 90 kilobytes up.

But see more you got to reverse the numbers when doing the home network thing. Your upload is others download. There download is your upload.