The minimum hardware requirements listed in the Setting Up the Environment manual are a suggested starting point. While that hardware configuration will run your iFIX system effectively, upgrading to an even faster processor and adding additional RAM to your computers will increase your system's performance.
You may also want to consider using SCSI drives rather than IDE drives. The use of SCSI drive systems may improve the speed of your open picture and replace picture operations.
Additionally, you may want to consider upgrading the graphics card in your PC to one with additional memory.
