Internet slows down heavily if I take out and put back in the ethernet cord in 10.7.2

Just got an the latest 21.5in iMac last weekend and I'm noticing an issue where the internet slows down if I take out and insert back in the ethernet cord.

I was having to do this to transfer over some files from my old comp via an ethernet-to-ethernet connection when I first noticed it. It seems to go back to normal if I renew the DCHP and do other tweaking to force OSX to reestablish the connection anew. Basically I can go from 15-20ms of ping delay to 50-52ms when this occurs.

Is this a known bug in 10.7.2 or in Lion so far or something?