Actually Andy i figured out the problem (i think..) and I'd like to discuss here so people that have similar problems can search the forums and see this post...
When i set my MTU to 1400 rather than 1500 i get almost normal internet performance. I'm not sure why but here is my setup. Nvnet -> LinkSys "network everywhere" router -> "cable" (its really a wireless internet thing..) modem.
The router defaults to 1500 mtu and maybe the problem is that with linux set to exactly the same size its causing problems??? I have no idea how the internals of networking work.
The problem that i'm experiancing is that I have to change my MTU to 1400 everytime i boot and the other problem i have is the RWIN, i cannot change it when i change the settings as suggested here http://www.psc.edu/networking/perf_tune.html#Linux
it does nothing to actually change my settings!! (I set RWIN much lower than they suggested)
Does anyone have any ideas how to deal with this? I cannot even get "Path MTU Discovery" to turn on even when i set the file to 1... it turns back to 0 on reboot too!
This is so frustering =[