In wireless cellular systems, Hybrid ARQ (HARQ) is used at the link level to guarantee a low BLER in spite of variations in the wireless link quality. However, HARQ retransmissions come at the cost of resources and impact the link throughput. We are interested in maximizing the link throughput in the presence of HARQ. We consider slow link adaptation over a correlated fading channel with full CSI-R. The attempted rate is based on the channel statistics and not the instantaneous realization. We consider the problem of selecting the throughput optimal attempted rate based on the channel statistics and SNR. We consider different approaches in accounting for memory in the channel, and characterize the performance gains from HARQ.