Super-fast Hardware for INFORMIX/XENIX

I wonder if any INFORMIX/UNIX/Hardware expert out there can help me choose an optimised hardware configuration to get the best out of INFORMIX standard-engine. I have a PC application utilising SCO-XENIX and INFORMIX-SQL/ESQL-C 2.1.3. The application is quite dependent on the database and the performance of the system is directly linked in with the speed of the database access. Hence, what I am looking for is information on how INFORMIX accesses the database so I can choose disk controller/drive which can support the way INFORMIX works. Some information on the databse itself. The total size of the databse is approximately 40MB, the largest table being 10MB. The row size vary from 40 bytes to 800 bytes. The update/inserts to the tables can occur from screen forms and ESQL/C applications. There are regular deletes of rows from tables. The updates/inserts/deletes frequently affect the same rows in the database. The configuration I have been recommended is a 66Mhz 486DX with 128k RAM Cache and 16Mb SIMMS Memory. For the disk I can choose either 340Mb SCSI hard drive with a fast access speed or twin 210Mb IDE disk with a built-in cache. I understand that its the performance of the disk that will the difference to the overall speed of the system, I need to decide whether to go fro SCSI drive with a faster access to the database or the IDE which has a built-in cache (which can presumably store recently affected rows and hence the next reference to the same rows do not require another disk access). I guess the ideal solution is to go for a fast access SCSI with a built-in cache but the hardware supplier tells me that you can not buy this. Any information appreciated. -- Satish Popat Ericsson, England, Tel +44 533 537534