What is Uniform Memory Access (UMA)? (Explained)

What is Uniform Memory Access (UMA)?

Uniform Memory Access, or UMA, refers to a balanced and shared memory architecture. All the processors in this particular architecture share the physical memory of the system in a uniform manner.

From a technical point of view, UMA is an architecture in which the access time to a location in the memory is independent of the processor creating a request for it or the memory chip itself, which stores the shared data.


  • Uniform Memory Access uses only one memory controller and therefore is a bit slower in comparison to NUMA architecture.
  • In UMA, the bandwidth is limited.
  • UMA typically uses three types of buses such as single bus, multiple bus, and crossbar switch.
  • Just as the name implies, the memory access time and latency in UMA are more balanced and uniform.
  • This specific architecture allows shared and balanced memory access, which is why it is also called the Symmetric Multiprocessor (SMP) system.

Understanding Uniform Memory Access (UMA)

Understanding Uniform Memory Access (UMA)

In a Uniform Memory Access architecture, all the processors in the system share uniform memory. This means that the access time and latency are not dependent on any of the following:

  • The processor wanting an access
  • The memory holding the data that a process wants to access

It is for this reason that the UMA architecture is best suited for network systems where time, purpose, and resources are all shared.

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This model typically expedites the execution of a program, even if it is large, therefore saving critical time.

Usually, there are three basic types of UMA architectures, such as:

  • UMA which uses Symmetric Multiprocessing (SMP) architecture that is bus-based
  • UMA which uses crossbar switches
  • UMA which uses multiphase interconnection networks

It is due to the design of this model that it is most suitable for creating multiprocessors of small size and with a single bus.

UMA is a specially designed memory organization that is most favored and commonly used in the shared memory ecosystems in order to provide the processors of all the systems in the ecosystem with an equal opportunity to read data from or write data to the memory.

It also helps the processor to process and store data.

In a common bus-structured SMP system, this is done by reducing disagreement on the bus. This is typically done by fetching the necessary data and instructions from each individual cache directly, as much as possible.

In some extreme conditions, such disagreement may even be reduced to zero when the cache memory is typically loaded from the universal memory.

This is because all data and instructions can possibly be contained completely in the cache.

Since UMA allows uniform access, the processors of the system are not discriminated against, and therefore less programming is required.

This means that the users with low authority are also not kept waiting to get access and process a task.

In standalone computers or those that are not connected to any network system may also have Uniform Memory Access, but it is quite redundant in such cases.

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It is because there is only one processor wanting access to the physical memory and no other contender for it.

What is Uniform Memory Access (UMA)

Why is UMA Important?

One of the main reasons that UMA is considered important is that it allows for the creation of a workflow which allows for managing the access to a set of resources for other members of a team, which would have been protected otherwise.

This specific type of memory access helps in maintaining data privacy and managing digital identity with its improvised legal and technical innovations.

It is also important for the specific authorization policies of it that are issued and managed by the central authorization server.


  • Uniform Memory Access uses a single memory controller, but in Non-Uniform Memory Access different memory controllers are used.
  • UMA performs at a slower rate in comparison to NUMA.
  • The bandwidth is limited in UMA, but the bandwidth in NUMA is more uniform.
  • UMA is typically used for general-purpose as well as time-sharing applications, but NUMA is used for real-time and time-specific applications.
  • The memory access time in UMA is more balanced and equal, but in comparison, the memory access in NUMA is not equal.
  • In UMA, there are three specific types of buses used, such as single, multiple, and crossbar, but NUMA uses only two namely, tree and hierarchical.

Where is UMA Used?

UMA is mainly used in time-sharing and general-purpose applications.

The architecture uses a shared physical memory in a uniform manner, which allows it to be used in parallel computers.

What is an Example of UMA?

In computer architecture, a few significant examples of the UMA model are Compaq Alpha Server GS, Sun Starfire servers, Silicon Graphics Inc. multiprocessor servers, and HP V series.

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Uniform Memory Access is the shared memory architecture used in the multiprocessor system.

There is a single memory used and accessed by all the processors in the multiprocessor system by means of an interconnection network.

The access speed and latency are the same for every processor in this model.

About Dominic Cooper

Dominic CooperDominic Cooper, a TTU graduate is a computer hardware expert. His only passion is to find out the nitty gritty of all computers since childhood. He has over 12 years of experience in writing, computer testing, and research. He is not very fond of social media. Follow Him at Linkedin