Dual Processors

We have a Dell Workstation 530, it has 2 processors. In device manager it shows 2 processors and the computer type is ACPI PC. In taskmanager under the performance tab it only shows 1 window, under the CPU history tab the only choice is 1 graph per CPU. I have tried to upgrade the driver for the computer in device manager, but I do not get a choice for multi processor ACPI PC. Is there an .INF file I can point to?