# memory buffer register

> register in a computer's processor, or central processing unit, CPU, that stores the data being transferred to and from the immediate access storage

**Wikidata**: [Q183380](https://www.wikidata.org/wiki/Q183380)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Memory_buffer_register)  
**Source**: https://4ort.xyz/entity/memory-buffer-register

## Summary
A memory buffer register (MBR) is a processor register within a computer's central processing unit (CPU) that temporarily stores data being transferred between the CPU and immediate access storage. It acts as a high-speed buffer for memory read/write operations.

## Key Facts
- **Classification**: Subclass of processor register, a type of immediately accessible working storage in digital processors.
- **Primary Function**: Stores data being transferred to and from immediate access storage (like RAM) during CPU operations.
- **Aliases**: Memory data register (MDR), MBR, registro de datos de memoria, RTM, Speicherpufferregister, 記憶體緩衝寄存器.
- **Differentiation**: Explicitly distinct from registered memory (a type of RAM module).
- **Identifiers**: Freebase ID `/m/051b8`; Microsoft Academic IDs 194240303 and 23417488 (discontinued).
- **Representation**: Present in 8 Wikipedia language editions (de, en, es, fa, fr, it, lmo, zh) under the title "Memory buffer register".
- **Wikidata Description**: Defined as "a register in a computer's processor, or central processing unit, CPU, that stores the data being transferred to and from the immediate access storage".

## FAQs
### Q: What is the main job of a memory buffer register?
A: The memory buffer register (MBR) acts as a temporary holding area within the CPU for data that is being moved between the processor and the immediate access storage, like RAM.

### Q: Is the memory buffer register the same as CPU cache?
A: No. The MBR is a specific register managing the direct transfer of data between the CPU and main memory (RAM). CPU cache is a separate, smaller, faster memory used to store frequently accessed data closer to the CPU core for quicker retrieval.

### Q: Why is the MBR important for CPU performance?
A: The MBR is crucial because it provides a high-speed buffer for the data transfer pathway between the CPU and main memory. A well-functioning MBR ensures that data can be moved quickly when needed, preventing the CPU from waiting unnecessarily for slower memory access.

## Why It Matters
The memory buffer register (MBR) is a fundamental component enabling efficient communication between a computer's central processing unit (CPU) and its main memory (RAM). By acting as a temporary staging area for data being read from or written to memory, the MBR minimizes the time the CPU spends waiting for data transfers to complete. This high-speed buffering is essential for overall system performance, as it helps bridge the significant speed gap between the ultra-fast CPU and the relatively slower main memory. Without a functional MBR, the process of retrieving program instructions and data from memory, or storing results back, would become a major bottleneck severely hindering computational speed and efficiency.

## Notable For
- **Specific Function**: Defined solely by its role as the CPU register holding data during transfers to/from immediate access storage, distinguishing it from other general-purpose processor registers.
- **Ubiquity**: Standard feature within virtually all modern CPUs, serving as a critical, though often implicit, component of the memory subsystem.
- **Minimalist Definition**: Defined by its singular, essential task in the CPU-memory data path, contrasting with registers handling other functions (instruction handling, arithmetic control).

## Body
### Core Definition
The memory buffer register (MBR) is a processor register located within the central processing unit (CPU). Its sole defined function is to store the data that is being actively transferred between the CPU and the immediate access storage (typically RAM).

### Classification and Relationships
- **Parent Class**: Belongs to the broader class of "processor register," which encompasses all immediately accessible working storage integrated into a digital processor.
- **Distinct Entity**: Is explicitly differentiated from "registered memory," which refers to a specific type of RAM module that incorporates registers on the memory module itself for signal integrity.

### Identification and Representation
- **Freebase ID**: `/m/051b8`
- **Microsoft Academic IDs**: 194240303 and 23417488 (discontinued service).
- **Wikipedia Presence**: Featured in 8 language editions (German, English, Spanish, Persian, French, Italian, Lombard, Chinese) under the consistent title "Memory buffer register".
- **Wikidata Definition**: Provides a clear definition: "register in a computer's processor, or central processing unit, CPU, that stores the data being transferred to and from the immediate access storage".

### Common Aliases
The MBR is known by several names across technical contexts and languages:
- Memory data register (MDR)
- MBR
- Registro de datos de memoria (Spanish)
- RTM
- Speicherpufferregister (German)
- 記憶體緩衝寄存器 (Chinese)

## References

1. Freebase Data Dumps. 2013