A new method of prefetching data blocks from the NVCache to the page cache in main memory and cascading prefetching n-blocks from a hard disk to the NVCache together was proposed to reduce the spin-up frequency of a hybrid hard disk drive and thus enhance I/O performance.The proposed method consists of three steps:1) Analyzing the pattern of read requests in block units;2) Determining the number of blocks prefetched to the NVCache; 3) Replacing blocks in the NVCache according to the block replacement policy,The proposed method can reduce the latency time of a hybrid hard disk and optimize the power consumption of an IPTV set-top box.Experimental results show that the proposed method provides better average response time compared to an existing adaptive multistream prefetching (AMP) method by 25.17％.It also reduces by 20.83％ the average power consumption over that of the existing external caching in energy saving storage system (EXCES) method.