Apparatuses, memory modules, and methods for performing intra-module data bus inversion operations are described. An example apparatus include a memory module comprising a data bus inversion (DBI) and buffer circuit and a plurality of memories. The DBI and buffer circuit configured to encode a block of data received by the memory module and to provide DBI data and a corresponding DBI bit to a respective memory of the plurality of memories.

Writing time is shortened even in a memory writing time for each access unit is not constant. A writing time prediction information holding unit holds writing time prediction information for predicting the writing time in a plurality of memory modules for each of a plurality of memory modules. A request selecting unit preferentially selects a write request of which longer writing time is predicted out of a plurality of write requests requiring writing in each of a plurality of memory modules on the basis of the writing time prediction information.

A memory module with multiple memory devices includes a buffer system that manages communication between a memory controller and the memory devices. Each memory device supports an access mode and a low-power mode, the latter used to save power for devices that are not immediately needed. The module provides granular power management using a chip-select decoder that decodes chip-select signals from the memory controller into power-state signals that determine which of the memory devices are in which of the modes. Devices can thus be brought out of the low-power mode in relatively small numbers, as needed, to limit power consumption.

A memory module with multiple memory devices includes a buffer system that manages communication between a memory controller and the memory devices. Each memory device supports an access mode and a low-power mode, the latter used to save power for devices that are not immediately needed. The module provides granular power management using a chip-select decoder that decodes chip-select signals from the memory controller into power-state signals that determine which of the memory devices are in which of the modes. Devices can thus be brought out of the low-power mode in relatively small numbers, as needed, to limit power consumption.

The embodiments described herein describe technologies for using the memory modules in different modes of operation, such as in a standard multi-drop mode or as in a dynamic point-to-point (DPP) mode (also referred to herein as an enhanced mode). The memory modules can also be inserted in the sockets of the memory system in different configurations.

The embodiments described herein describe technologies for using the memory modules in different modes of operation, such as in a standard multi-drop mode or as in a dynamic point-to-point (DPP) mode (also referred to herein as an enhanced mode). The memory modules can also be inserted in the sockets of the memory system in different configurations.

A memory module is operable in a computer system having a memory controller and a system bus and comprises memory devices organized in one or more ranks and in a plurality of groups, and circuits configurable to receive from the memory controller a system clock and input control and address (C/A) signals, generate a module clock signal and module C/A signals in response to the system clock and input C/A signals, generate a plurality of local clock signals corresponding, respectively, to the plurality of groups of memory devices, and output the plurality of local clock signals to respective groups of the memory devices. A respective local clock signal has a respective phase relationship with the module clock signal and is output to a corresponding group of the memory devices that includes at least one corresponding memory device in each of the one or more ranks.

A memory module is operable in a computer system having a memory controller and a system bus and comprises memory devices organized in one or more ranks and in a plurality of groups, and circuits configurable to receive from the memory controller a system clock and input control and address (C/A) signals, generate a module clock signal and module C/A signals in response to the system clock and input C/A signals, generate a plurality of local clock signals corresponding, respectively, to the plurality of groups of memory devices, and output the plurality of local clock signals to respective groups of the memory devices. A respective local clock signal has a respective phase relationship with the module clock signal and is output to a corresponding group of the memory devices that includes at least one corresponding memory device in each of the one or more ranks.

A memory module can be programmed to deliver relatively wide, low-latency data in a first access mode, or to sacrifice some latency in return for a narrower data width, a narrower command width, or both, in a second access mode. The narrow, higher-latency mode requires fewer connections and traces. A controller can therefore support more modules, and thus increased system capacity. Programmable modules thus allow computer manufacturers to strike a desired balance between memory latency, capacity, and cost.

A memory module can be programmed to deliver relatively wide, low-latency data in a first access mode, or to sacrifice some latency in return for a narrower data width, a narrower command width, or both, in a second access mode. The narrow, higher-latency mode requires fewer connections and traces. A controller can therefore support more modules, and thus increased system capacity. Programmable modules thus allow computer manufacturers to strike a desired balance between memory latency, capacity, and cost.