This research proposes a selective compressed memory system (SCMS) focusing on a compressed cache architecture, in which only data blocks with good compression efficiency are compressed selectively and all compressed blocks are stored in a fixed memory space. The selective technique compression can reduce decompression overhead caused by an on-line data decompression and also the fixed memory space allocation allows efficient management of the compressed blocks. The results from trace-driven simulation show that the SCMS approach can provide around 35% decrease in the on-chip cache miss ratio as well as a 53% decrease in the data traffic over the conventional memory systems. Furthermore, a large amount of the decompression overhead can be reduced, and thus the aver-age memory access time can also be reduced by maximum 20% against the conventional memory systems.