Dell D810/FreeBSD 6.1-PRERELEASE/interrupts??

[Anthony Maher]

Hello,

finally bit the bullet and upgraded my Dell D810 to RELENG_6
from latest 5.
All seemed to go well but certain things are slow/odd.
X startup is slow but once running everything seems mostly ok.
Rebuilding ports and they seem to be rebuilding ok.
On shutdown the sync operation takes far longer and 
get vnodes remaining numbers like
77777777777777777777777777777777777777774444444444444444433444
44422222222222222222122222211111111111000000000000000000000000
0000000
which is really odd.
The second hand on emiclock jumps typically in intervals of 5 or more seconds.  If I run somnething like "find /" then the
second hand clicks over smoothly in 1s jumps.
Unplugging and replugging in usb mouse takes a while for it to be recognized.  Again if system is busy then it gets recognized quickly.

I added kern.hz="100" to loader.conf but still the same behaviour.  

It feels like some sort of interrupt problem but vmstat looks
ok except I'd expect that cpu0 would have a rate of 100???

vmstat -i
interrupt                          total       rate
irq1: atkbd0                        3777          2
irq9: acpi0                            1          0
irq12: psm0                         2070          1
irq13: npx0                            1          0
irq14: ata0                        10642          6
irq15: ata1                           41          0
irq16: pcm0 bge0++                  1828          1
irq18: uhci2                       20771         13
cpu0: timer                        65570         41
Total                             104701         66

This is a generic kernel, no weird make.conf vars.
Some sort of ACPI problem???

Any suggestions?
thanks
--
tonym