A method includes, in a computing system (20) that includes one or more compute nodes (24) that run clients (32), defining memory chunks, each memory chunk including multiple memory pages accessed by a respective client. Respective similarity-preserving signatures are computed for one or more of the memory chunks. Based on the similarity- preserving signatures, an identification is made that first and second memory chunks differ in content in no more than a predefined number of memory pages with at least a predefined likelihood. Efficiency of access to the identified first and second memory chunks is improved.