Provided are methods and systems for memory decompression using a hardware decompressor that minimizes or eliminates the involvement of software. Custom decompression hardware is added to the memory subsystem, where the decompression hardware handles read accesses caused by, for example, cache misses or requests from devices to compressed memory blocks, by reading a compressed block, decompressing it into an internal buffer, and returning the requested portion of the block. The custom hardware is designed to determine if the block is compressed, and determine the parameters of compression, by checking unused high bits of the physical address of the access. This allows compression to be implemented without additional metadata, because the necessary metadata can be stored in unused bits in the existing page table structures.