FC5, getting ata2: command 0x25 timeout, stat 0x50 host_stat 0x4

[Andy Campbell]

My install of FC5 will work quite happily for a while, any where from 
20mins
to a couple of hours and then it will essentially hang, I can run 
commands but
they take a VERY long time to execute.

On the console I get the following message ....

ata2: command 0x25 timeout, stat 0x50 host_stat 0x4

All references I've found on the web seem to suggest its a drive failing,
but I don't believe this is the case, as FC4 is still running very 
stably from
another partition on the same drive, and I've run the Hitachi diagnostic
software and it reports no error, neither does SMART report any problems.

I'm using the a the latest FC5 kernel,  2.6.16-1.2080_FC5smp.

Motherboard : Abit AV8 3rd-Eye
Chipset : VIA K8T800 Pro + VT8237

Hardrive :  SATA Hitatchi 160Gb ......

 *-disk:1
               description: SCSI Disk
               product: HDS722516VLSA80
               vendor: ATA
               physical id: 1
               bus info: scsi at 1:0.0.0
               logical name: /dev/sdb
               version: V34O
               serial: VN6D3ECDDHME0D
               size: 153GB

Any ideas how to fix this, I noticed the version on libata has changed 
from v1.10 ( 2.6.15-1.1833_FC4smp ) to  v1.20
in 2.6.16-1.2080_FC5smp could this be a problem ?

Thanks
Andy