5.9MB/sec on a 10BaseT or 100BaseT network? If 10BaseT, don't complain! If 100BaseT, make sure all NICs on your network are actually connecting to the switch at 100/full-duplex. If so, try using different cables (the shortest needed to fit your needs; don't use a 300ft cable to connect 2 pcs only 5 feet apart).
-j