Shared server memory usage

[Chucks_k]

Hi all,

We have Oracle 10.1.0.3 intalled on a Redhat linux box. The server has 4GB of physical memory. Oracle has been configured to shared servers (wasnt configured by me, i would used dedicated servers). We have 25 shared servers. Now when I do a top i see:

195 processes: 190 sleeping, 3 running, 2 zombie, 0 stopped
CPU states:  cpu    user    nice  system    irq  softirq  iowait    idle
           total    4.1%    0.0%   65.2%   0.0%     0.7%   29.0%    0.7%
           cpu00    3.7%    0.0%   64.6%   0.0%     1.5%   28.5%    1.5%
           cpu01    4.5%    0.0%   65.9%   0.0%     0.0%   29.5%    0.0%
Mem:  3921888k av, 3899804k used,   22084k free,       0k shrd,    7960k buff
                   2963208k actv,  566312k in_d,   55244k in_cK
Swap: 2044072k av,    5168k used, 2038904k free                 3408592k cached
0m
7m  PID USER     PRI  NI  SIZE  RSS SHARE STAT %CPU %MEM   TIME CPU COMMAND
29453 oracle    16   0 1110M 1.1G 1107M R    28.6 28.9  12:38   0 oracle
    8 root      16   0     0    0     0 SW   28.2  0.0 218:07   0 kscand
    7 root      16   0     0    0     0 SW    3.0  0.0 212:15   1 kswapd
29455 oracle    15   0 1041M 1.0G 1030M R     2.2 27.0   4:19   0 oracle
29449 oracle    15   0 1136M 1.1G 1124M D     1.8 29.5  33:03   0 oracle
25029 root      20   0  1244 1244   880 R     1.5  0.0   0:00   0 top
29451 oracle    15   0 1124M 1.1G 1112M D     1.1 29.2  35:58   1 oracle
29457 oracle    15   0 1022M 1.0G 1019M D     0.7 26.6   4:06   0 oracle

As can be seen, most of the memory is been used by oracle processes, these were traced to shared processes (some using 1.1G!). Besides changing to dedicated mode, what areas need to looked in order to reduce this overhead?
SGA_TARGET is set to 1.4GB, and PGA_AGGREGATE=486MB.

Any advice will be much appreciated,

Thanks in advance,
Chucks