Urgent Sun Informix Performance Problem

Dear users, we are running the following configuration: SUN SPARC CLASSIC - 96 MB RAM - 535 MB Internal Hard drive - 535 MB External hard drive - 1.05 Gigabyte External hard drive ...running the Solaris 2.3 Operating System ...and INFORMIX ON-LINE Version 5.x Our problem: SQL queries and SELECT statements of any sort grab all available CPU time and allow no other user requests to be processed, thus reducing the system to an almost full stop (snail's pace). 'vmstat' verifies that zero percent (0%) CPU time is available whilst any SQL requests are being processed. We have been completely through the Informix guide on 'optimization'... our SWAP SPACE and SHARED MEMORY have been optimized as per recommendations from Informix. If you are running the above configuration and have any information regarding the optimization or speeding up of system performance, please do not hesitate to contact us directly. Thanks in advance. Our internet address: paul@rswa.DIALix.oz.au (please don't send to QSoft... they helped us by lending their login)