Set the -iqnumbercpus startup switch to specify the number of CPUs available. This parameter overrides the physical number of CPUs for resource planning purposes.
On machines with Intel® CPUs and hyperthreading enabled, set -iqnumbercpus to the actual number of cores
On machines where an operating system utility has been used to restrict Sybase IQ to a subset of the CPUs within the machine
See “Setting the number of CPUs” in System Administration Guide: Volume 1 > Running Sybase IQ.