Please take this all with a grain of salt as this is out of my area but:
as always did anything change in the whole environment at the time of performance degradation?
Is this the only thing on your network that is slowed or are there other traffic issues (maybe not as severe)?
my server is the same physical distance but we had some serious speed issues that ended up being various network/hardware issues:
e.g.server hardware failing, loose wires (tech tripped and pulled them), over heating component, bad array, failed router switch , and other stuff
Ask your network/hardware folks to review EVERYTHING that has been done to any part of the network set up, especially on the day you saw the issue (or weekend before if it was monday).
Edited by DBlank - 24 Nov 2010 at 3:50am