The command that reduces the amount of time it takes to complete the ISSU on a Cisco Nexus 7000 series switch that has dual supervisor modules and two I/O modules is install all kickstart <image>system<image>parallel. This command performs a parallel upgrade of the kickstart and system images on all modules, which reduces the downtime and speeds up the ISSU process. The other commands (install all epld bootflash:<image> and install all kickstart<image>system<image>) do not perform a parallel upgrade and take longer to complete the ISSU. References: For more information on how to perform an ISSU on a Cisco Nexus 7000 series switch, please refer to the following resources: * Cisco Nexus 7000 Series NX-OS Software Upgrade and Downgrade Guide * Cisco Nexus 7000 Series NX-OS ISSU Upgrade Guide