In some examples, performance counters for computer memory may include ascertaining a request associated with a memory address range of computer memory. The memory address range may be assigned to a specified performance tier of a plurality of specified performance tiers. A performance value associated with a performance attribute of the memory address range may be ascertained, and based on the ascertained performance value, a weight value may be determined. Based on the ascertained request and the determined weight value, a count value associated with a counter associated with the memory address range may be incremented. Based on an analysis of the count value associated with the counter, a determination may be made as to whether the memory address range is to be assigned to a different specified performance tier of the plurality of specified performance tiers. Based on a determination that the memory address range is to be assigned to the different specified performance tier, the memory address range may be assigned to the specified different performance tier.