Performance. .oO(not AGAIN!)

Hi there, here is another performace problem posting. I've read the FAQ but haven't actually found something that fits. The system in question is an older HP 9000/847 with HP-UX 9.0 and Online 5.0 running on it. It has 128 MBytes of Memory and a HP SCSI Harddisk containing Informix' raw partition. The application running on this system is a larger DB application with about 36 tables, each containing 1 to 1.000.000 rows. There are several procs of various kinds working on that data; the idea is that people call the datacenter and take some action on their data. Currently there are about 64 sqlturbo processes, each one possibly running some instances of sacego at some time. When the data center started in '92 performance was nothing to think about. But now we get into some trouble. So here are my questions: At times of high throughput the operators suffer from response times of about 10 seconds. Sometimes they get the ISAM Error -154 (Deadlock timeout expired - possible deadlock). I've looked up the program sources and found something like EXECUTE IMMEDIATE SET LOCK MODE TO WAIT 10; Did this cause the error or may there really by a deadlock? And, more important: What can be done to improve performance? I don't think there is much to do with the code, nor is it a problem of UPDATE STATISTICS (I've tried that! only marginal improvement). If there wassome money to spend on Hardware, what would you suggest? Can Online stripe the raw partition on several disks? (I've used glance, a performance monitor. It shows CPU and disk as bottlenecks). Any ideas?? TIA, Daniel