7.x performance issue on DEC Alpha

We are currently having some serious performance problems when using 7.x on DEC Alpha running Dec Unix 3.12B. We have two alphas. Alpha I runs the Informix database engine and about 30 users and Alpha II runs about 150 users during peak time. Both alphas have two CPUs each and about 1 GB of main memory and 2GB of swap space. The Alphas are 2100 model 4/275. Alpha II which basically runs our application for about 150 users works fine. The load average hardly goes above 1 during peak times. Alpha I which runs similar 30 users and informix server has serious performace problems and keeps on running out of CPU cycles. The load average shoots up to 20-30 and them comes back quickly to 2-3 etc. Sometimes it even goes upto 40-50 within seconds. We have been working with Informix support/consultant to try to resolve this issue and have so far done the following things : 1. Reduced the number of CPU VP from two to one. In this case the CPU became free but each and every select query within database started to take 20-30 seconds. 2. We were told that sometimes if OPTCOMPIND value is not set to 0 it transforms the Informix engine to "one query at a time" and that might be the reason for serious performance degradation when we reduce the number of CPU VPs to one. We tried with value set to 0...Still no improvements. 3. Another info which we were given was that performance degrades more than 10 times if number of share memory segments allocated exceeds 3. We have adjusted our onconfig so that we do not allocate more than 2 shared memory segement for our peak usage. Performance is still the same. Any help in resolving this will be very much appreciated. Please send email to rmishra@raileurope.com. or Fax(914)682-5236 or call (914)681-3291 - Rakesh Mishra