large memory utilisation by database

Hi All,
I continue to see more often in the past few days alerts from grizzly
memory utilization. It ranges between 63% and 73% physical utilization, over
the 70% existing threshold. While we were getting those alerts, AMUASPR was
the highest utilization, and we could see 156 simultaneous database
connections.But sga_max_size is just 1616MB and i am not sure how its consuming 8 gb of memory .


Starting memory test on Grizzly at Fri Oct 26 18:06:50 GMT 2007 Physical RAM
= 24541MB

3543.79 MB Shared memory currently in use.

Memory Stoat total used avail %used
physical 24541.0 17339.1 7201.9 71%
active virtual 13347.7 8094.8 5252.9 61%
active real 11036.3 6108.9 4927.3 55%
memory swap 19005.2 3868.5 15136.7 20%
device swap 22080.0 11568.9 10511.1 52%

amufspr - 8580.0 MB--this is the db running on 10gr1 hpux 11.2
appuaspr - 418.6 MB
drforte - 13.9 MB
forte515 - 12.6 MB
lp - 3.4 MB
nagios - 0.2 MB
onames - 5.3 MB
orauaspr - 20638.7 MB
rbalcu - 2.0 MB
root - 468.4 MB
=========================
Total - 30143.2 MB

post all your memory sizing parameters.