[CentOS] SAR

Folks,

    At what point in iowait should I start to worry about having a 
bottleneck, or is this something that can't be answerd with a single 
integer?  According to sar, after my last reboot to turn off 
hyperthreading as a test, at one time, I see 4.9% iowait, but then one 
minute later, it droped back to 0.01%, and rarely even gets to 1.0%, at 
least what I remember from yesterday.  ?

thanks....

Sam