Some embodiments of the invention provide a programmable system in package (“PSiP”). The PSiP includes a single IC housing, a substrate and several IC's that are arranged within the single IC housing. At least one of the IC's is a configurable IC. In some embodiments, the configurable IC is a reconfigurable IC that can reconfigure more than once during run time. In some of these embodiments, the reconfigurable IC can be reconfigured at a first clock rate that is faster (i.e., larger) than the clock rates of one or more of the other IC's in the PSiP. The first clock rate is faster than the clock rate of all of the other IC's in the PSiP in some embodiments.