low breezy hard disk performances

[Robert Fleming]

Could this be an underlying issue with ram?  What does vmstat bring 
back? Are there any file system errors being logged. 

Have you updated the kernel to include the necessary drivers for your 
hardware?  It could be possible to have a driver that isn't handling the 
hardware correctly and is causing the disk to fall out of dma mode there 
by slowing performance. 

It could also be that there is a filesystem driver that is not playing 
nicely and is causing high io but isn't registering.  Are you running a 
jounaled file system?  What are the logs saying for the file system?

Are you having any latency issues with your network connections?  On 
ocassion I have seen issues where the hardware isn't functioning 
correction and causing high io on the bus. If it's a regular pc you 
could pull the card just as a check.

Are you running the system memory clock at a higher speed than the ram 
supports?  Are you getting any memory errors?

Are you running a disk controller that has been around the linux 
environment for a while?  Are there any kernel patches for your specific 
hardware that have been udpated?

Just questions..