1. A method for designing a system on a target device, the method comprising: assigning resources on the target device to static logic modules and partial reconfigurable (PR) modules in the system; performing one of placing and routing the static logic modules with resources assigned; re-assigning un-used assigned resources of the static logic modules to the PR modules; and performing one of placing and routing instances of one of the PR modules on the target device in parallel with the resources assigned, wherein a first instance of a PR module is one of placed and routed using a first processing resource in parallel with a second instance of the PR module that is placed and routed using a second processing resource.