[nsp] intermitten ping lags on 7500/rsp4/256M

[lexus]

I am running several 7500/rsp4/256M...BGP to the outside, OSPF on the
inside.  Just one small OSPF area involving about 7 routers.

The problem:  Every other 10 to 40 secs, if I leave a continuous ping to
the router interface or outside hosts passing thru the router, the ping
time would jump from 0msec to 600msec for 1 packet, then down to 0msec,
20 secs later, another packet going out at 600msec...and so on.

I have tried to mess with cef/dcef to no availability.  Tried reloading
diff IOS images, from 12.0 to 12.2 (mostly IP and or Service
Provider/VIP images), same problem.

I am out of ideas...this intermitten ping lag is driving me crazy.  Any
help/direction is greatly appreciated.

Thanks
-ken