I should have asked this before. OOPS You do have an interesting problem. I hope we can help you fix.

What Oracle Version are you running on your server?

Also type the following commands and show us the output:
1) Info about Shared memory: ipcs -A
2) What is your current swap: swap -s
3) How many processors:
/usr/sbin/psrinfo -v |grep "Status of processor"|wc -l
4) Top 6 process hogs: ps -ef|sort +6| tail
5) Display Ram Size: prtconf| grep -i mem

Check your Alert log for ORA- errors. Are there any? If so what?

Check your /var/adm/messages file for unusual errors.

Just a few troubleshooting ideas. Have you tried Metalink?