Ask Difference

Synchronous DRAM vs. Asynchronous DRAM — What's the Difference?

By Fiza Rafique & Maham Liaqat — Published on February 22, 2024
Synchronous DRAM (SDRAM) operates in sync with the system clock, enhancing efficiency and speed, whereas Asynchronous DRAM operates independently of the system clock, resulting in slower data access times.
Synchronous DRAM vs. Asynchronous DRAM — What's the Difference?

Difference Between Synchronous DRAM and Asynchronous DRAM


Key Differences

Synchronous DRAM (SDRAM) and Asynchronous DRAM are two types of dynamic random-access memory (DRAM) used in computing systems to store data temporarily. The key difference between them lies in their operation relative to the system clock.
Synchronous DRAM (SDRAM) is designed to run at the same speed as the system clock. This synchronization allows for quicker and more efficient data handling, as it can queue up commands and execute them in a tightly controlled sequence. The introduction of SDRAM marked a significant improvement in memory technology, allowing for higher bandwidths and speed because of its ability to align memory access times with the system clock cycles. This feature is particularly beneficial in systems where the processor speed and memory demands are high, as it minimizes the latency between memory and processor interactions.
Asynchronous DRAM, on the other hand, operates independently of the system clock. This means that each memory access operation is initiated and completed without waiting for a clock signal, leading to variable response times. While asynchronous DRAM was simpler and more cost-effective to produce and implement in early computing systems, its performance is significantly lower compared to SDRAM. The lack of synchronization with the system clock can cause delays in data retrieval and processing, making it less suitable for applications requiring high-speed data access and processing.
The transition from asynchronous DRAM to SDRAM was driven by the increasing need for faster memory systems that could keep up with the accelerating speeds of processors. SDRAM's ability to synchronize with the system clock enables more predictable and efficient data transfer rates, making it a cornerstone of modern computing memory architectures.
In terms of application, SDRAM has become the standard in many computing environments, from personal computers to servers, due to its superior speed and efficiency. Asynchronous DRAM, while largely phased out in favor of faster synchronous variants, laid the foundational technology for the development of more advanced memory types.

Comparison Chart

Clock Synchronization

Yes, operates in sync with the system clock.
No, operates independently of the system clock.


Higher, due to synchronized operations.
Lower, due to lack of synchronization.


More efficient in data handling and bandwidth.
Less efficient, with variable response times.


Generally higher due to complexity.
Lower, simpler in design and production.


Preferred in high-speed computing environments.
Used in earlier computing systems, now less common.

Compare with Definitions

Synchronous DRAM

Memory that synchronizes with the system clock for efficient data processing.
Modern PCs use SDRAM for faster application performance.

Asynchronous DRAM

Has been largely replaced by faster synchronous types.
Asynchronous DRAM is now rare, with SDRAM and DDR variants preferred.

Synchronous DRAM

Enables sequential access aligned with clock cycles.
High-speed servers utilize SDRAM to enhance data retrieval speeds.

Asynchronous DRAM

Marked the early evolution of computer memory technology.
Asynchronous DRAM was a stepping stone in the development of modern memory systems.

Synchronous DRAM

Supports higher bandwidths by queuing commands.
Gaming computers leverage SDRAM's bandwidth for real-time processing.

Asynchronous DRAM

Simpler and cost-effective, but with slower performance.
Budget computing devices initially favored asynchronous DRAM for its lower cost.

Synchronous DRAM

Became a foundation for DDR (Double Data Rate) RAM.
SDRAM's technology paved the way for DDR RAM in advanced computing systems.

Asynchronous DRAM

Suited for less demanding computing applications.
Some embedded systems may still use asynchronous DRAM where speed is not critical.

Synchronous DRAM

More complex and costly, but offers superior speed.
SDRAM is a standard choice in performance-critical computing devices.

Asynchronous DRAM

Operates independently of the system clock, leading to variable speeds.
Early personal computers often used asynchronous DRAM.

Common Curiosities

How does the transition from asynchronous to synchronous DRAM affect computing performance?

The transition significantly enhances computing performance by reducing memory access times and increasing data processing speeds.

What is the main advantage of SDRAM over asynchronous DRAM?

The main advantage is SDRAM's synchronization with the system clock, which increases data transfer efficiency and speed.

Is asynchronous DRAM still used today?

While its use has significantly decreased in favor of faster memory types, it may still be found in some low-speed or older applications.

What are the implications of SDRAM's clock synchronization for gaming computers?

For gaming computers, clock synchronization means smoother gameplay, faster loading times, and the ability to handle more complex game environments.

Why might a device still use asynchronous DRAM?

Devices with lower processing speed requirements or those designed before the widespread adoption of SDRAM might still use asynchronous DRAM for its simplicity and lower cost.

How does asynchronous DRAM handle data transfers?

It handles data transfers independently of the system clock, leading to less predictable access times compared to SDRAM.

Why is SDRAM more expensive than asynchronous DRAM?

SDRAM's higher cost is attributed to its more complex design, which enables synchronization with the system clock and higher performance.

How do motherboard specifications influence DRAM choice?

Motherboard specifications determine the type of DRAM supported, based on the memory technology and speed the motherboard architecture is designed to accommodate.

Can SDRAM and asynchronous DRAM be used interchangeably?

No, they are not interchangeable due to differences in operation and compatibility with different motherboard architectures.

What technological advancements followed SDRAM?

SDRAM technology laid the groundwork for DDR RAM variants, which offer even higher speeds and efficiency by transferring data on both the rising and falling edges of the clock signal.

Share Your Discovery

Share via Social Media
Embed This Content
Embed Code
Share Directly via Messenger

Author Spotlight

Written by
Fiza Rafique
Fiza Rafique is a skilled content writer at, where she meticulously refines and enhances written pieces. Drawing from her vast editorial expertise, Fiza ensures clarity, accuracy, and precision in every article. Passionate about language, she continually seeks to elevate the quality of content for readers worldwide.
Co-written by
Maham Liaqat

Popular Comparisons

Trending Comparisons

New Comparisons

Trending Terms