UPDATE 03/25/2015 9:00am CST: Server has been running as normal for over a day; fixed.
UPDATE 03/23/2015 1:09pm CST: Network ops folks have addressed the issue and speed has been back to normal for about ten minutes. We'll continue to monitor the servers to make sure that all the issues have been addressed.
Two of our front-line webservers are under heavy load. Operations folks are taking a look and we will report back when the problem has been identified.