I would perform a clean boot and see if the problem goes away..If it goes away, start systematically reenabling the non-Micro$oft services to see which one causes the problem..I expedite the process by reenabling the non-Micro$oft services in groups of 10 (or whatever you want) at a time because reenabling them individually will take f-o-r-e-v-e-r..When a group is found that the problem occurs in, then start individually reenabling the services in that group until the problem service is found..Hopefully you can isolate it to a service that's related to some borked/bogus/problematic program and deal with it from there..There could even be a problematic Micro$oft service too..Check the Startup group items too..Can't say I've had a network issue like that, but I've had services cause other problems like extremely high CPU usage..If all else fails, I suppose a clean Windows install would be due.

Wanted to add, this only happens upon initial boot up of PC. I did another complete removal of NIC drivers, ran some registry cleaner and defrag, removed some potential background apps, reboots, and installed drivers again. Seems to have fixed the issue.
 
I usually always have my PC on or it auto sleeps, so the issue didn't always occur unless for some reason I needed to restart my PC, in which upon boot up I would see the network gadget displaying full bandwidth speed download. Then proceeded to reboot the PC to make it stop, and this would fix it.
 
Nonetheless, I hope the issue is fixed, I've simply been lazy or busy to properly address my concerns and wanted to get some second opinions. Thanks for the input.

May or may not be related, but a popular chrome app was found to be doing something like that:
http://www.kitguru.net/ch...bandwidth-for-botnets/