[BlueOnyx:19472] weird bandwidth slowdown

[Tom]

Ever since the last large YUM Update, around the end of March, I have been 
experiencing a weird anomaly. Using Raqbackup as an example:
Normally I achieve 25 to 30 mbps transfer speeds for the backups, and the 
backups complete very quickly. Over the course of a week, they slow down 
to 2- mbps and the backup takes hours. I re-boot the server and everything 
is back to normal again. I've checked cables, cards, switches, logs, etc 
and nothing shows why this is happening. 
I'm stumped. 
Any input will be greatly appreciated.
Thanks in advance
Tom