Informix "hardware bottlenecks"

Hello, everybody, the situation is following: Our software developers are going to test their OLTP application. For testing purposes they currently are building a server - they can expand server without problems, money is not a big essence here OS is Windows NT, IDS 7.31. Its HP server LH6000. Currently it has 1 Xeon CPU 700 MHz with 2 MB cache, and it can be expanded to 6 CPU's. Built-in UltraSCSI2 RAID 2-channels controller with 32 MB cache, which can be upgraded to 128 MB. 1 GB RAM, expandable till 8 GB. 6 discs with 19GB each. So far about hardware. They want to test application with different hardware configurations, and draw nice graphs and see, which configuration is optimal. Now, could I ask for Your advice? Which hardware components and in what way impact performance of IDS? How important is RAID controller's cache memorys size? Recommended RAID level? (RAID 5 or RAID 10 or else)? My purpose here is to get some guidelines of what hardware parts should be boosted to maximum, and which are not so important. Hoping on Your expertise with best regards Andris Shirons