Multi-CPU or hyperthreaded machines may experience issues.
Sybase IQ runs most efficiently when it knows how many physical CPUs are available to it. On a machine with hyperthreads turned on, or where Sybase IQ is unable to access all of the available CPUs, Sybase IQ will create too many threads and run less efficiently than it should.
Start the server with -iqnumbercpus set to the number of CPUs available to Sybase IQ, overriding the physical number of CPUs.
For details on start_iq database options, see the Utility Guide.