Sure, that's where I found out how to further improve transcoding with CoreAVC, and where I found (and tried) tricks like forcing half-duplex on the network, limiting the bandwidth like this thread says and numerous other things. Nothing works.
Obviously the connection/cabling is fine; traces show a 90 - 96 Mbit/s connection to the PS3, the PS3 downloads games and updates flawlessly and to the full extent of my internet connection, torrents on my PC simply fly... It's all fine and dandy - but the media server never goes over 1 Mbit/s while sending data (the buffer is, I repeat, full, no transcoding issues - the same happens on the poorest video quality too).
I fail to see the network bottleneck.