SDRAM vs. RAM: What’s the Difference?

Random access memory (RAM) is a critical component in any computer. SDRAM is a type of DRAM, which is a type of RAM, that is widespread because of its speed and efficiency.

Regardless of whether you use your computer for gaming, work, or anything else in between, you may be curious how SDRAM or RAM may make your computer use more seamless and efficient.

Our expert team has broken down what exactly SDRAM is and how it differs from conventional RAM formats to help you select the right type of memory for your computer. 

What is SDRAM?

Synchronous Dynamic Random Access Memory (SDRAM) is a type of DRAM, which stands for Dynamic Random Access Memory, that has been widely adopted in computing because of its fast speeds.

SDRAM is synchronous (hence the name), while conventional RAM is asynchronous. This means that it does not synchronize the memory access for the RAM with the computer’s system clock or timer.

Data left in this type of RAM remains accessible for a long period after a program accesses the data, which can lead to the variable performance of the memory and slowing of its processes. SDRAM synchronizes with the system clock and can operate with greater speed and complexity.

SDRAM is so efficient that it can keep two sets of memory addresses, alternating data between them to reduce the delays that are common with asynchronous RAM. SDRAM can even accept new instructions while an existing request is in progress, completing write commands without a pause and completing read requests with extremely low latency. 

Types of SDRAM

SDRAM is the predominant format of Dynamic RAM and has numerous generations, each with increasing speed. There are many double-data-rate RAM versions of SDRAM including DDR2, DDR3, DDR4, and DDR5.

The History of SDRAM

The development of SDRAM goes back to the 1970s.

The prototype version of this type of RAM was used in Intel processors. The first robust commercial version was released by Samsung in 1993, with standardization by JEDEC and rapid adoption following. By the year 2000, SDRAM was the main form of DRAM used in computing. Double-data-rate versions of SDRAM became available in the early 2000s and increased in speed and performance.

Demand remains high for SDRAM because of its simple design, low cost, and high speed.

What is RAM?

RAM is short for Random Access Memory. It is a leading computer memory technology that is characterized by its ability to read and write in any order, with faster speeds than other memory components like hard-disk drives (HDD), optical drives (OD), or solid-state drives (SSD).

RAM memory storage uses a semiconductor component that holds the computer’s operating system files and working data. RAM comes in many forms, and the specifications of RAM significantly affect the speed and performance of computers. 

RAM is a type of volatile memory. This means that the stored data remains as long as the computer has power.

This quick and accessible memory is for short-term tasks and has integrated connectivity so information in longer-term memory storage can be accessed. When the temporary files are not needed or in use, the RAM is wiped.

You’ll find the RAM module on the motherboard of your computer. It connects to the motherboard via Small Outline Dual In-line Memory Module (SODIMM) slots near the CPU socket so that it can pull hard drive data for the CPU and GPU to work with. 

Key Types of RAM

Though there are many RAM formats, we can broadly divide RAM into dynamic and static RAM.

Dynamic RAM (DRAM) stores individual bits of memory in its memory cells, whereas static RAM (SRAM) uses latching circuitry to store memory. 

A Quick History of RAM

Freddie Williams and Tom Kilburn of Manchester University invented RAM in the late 1940s in the United Kingdom.

The Williams–Kilburn tube (1947) was a cathode ray tube that stored data as charged spots for the early Manchester ‘Baby’ computer.

RAM was further refined by a variety of academic and commercial organizations as computing transitioned from mechanical to electronic functions. Key advancements in the development of RAM include:

• The synchronization of RAM with computer processors in the 1990s
• The transition from single data rate RAM to double data rate RAM in the early 2000s

What’s the Difference Between SDRAM and RAM?

SDRAM is a type of RAM, and it is volatile storage that loses its data when it loses its power supply.

Both SDRAM and RAM are essential for the normal function of a computer. However, when SDRAM is compared to predecessor RAM formats, there are several notable differences and key features that make SDRAM distinct.

Unlike generic RAM, SDRAM synchronizes to the clock of the processor and the bus for enhanced efficiency and speed. This means that the rising edge of an externally supplied clock signal controls the operation of its external pin interface.

SDRAM is significantly faster than the earlier forms of RAM. Its latency is not always lower, but SDRAM can interleave requests to perform more quickly. Double-data-rate SDRAM further increases processing speeds by extremely strict timing of its electrical data and clock signals.

SDRAM has higher power consumption than other forms of RAM. For example, SDRAM has a working voltage of 3.3 volts versus 1.8 to 2.5 volts for other common RAM formats.

SDRAM modules have an extremely fast prefetch timing. This process involves moving memory from longer-term, slower memory to faster, local memory to boost performance. 

SDRAM vs. RAM: A Side-by-Side Comparison

Similarities and Differences

SDRAM is a type of RAM, but that is, for the most part, where their similarities end.

Similarities

• SDRAM and VRAM are both types of computer memory located on the motherboard.
• SDRAM and RAM are essential modules for the normal function of a contemporary computer or laptop.
• SDRAM and RAM are volatile and will lose stored memory if their power supply is interrupted.

Differences

• SDRAM is faster and more efficient than other forms of RAM.
• RAM is asynchronous and sends its signals independently to the system clock cycle.
• DDR versions of SDRAM have extremely fast data rates as they can use both edges of the clock. 
• SDRAM has an access time of 16 to 12 nanoseconds.
• RAM has lower power consumption than SDRAM.

What is SDRAM Used For?

SDRAM is the main short-term memory in most contemporary computers and handles all the data that is in current use. Current data used by the operating system (OS), browser, and software applications is stored in RAM for quick and easy access. 

Your computer relies on its RAM to complete routine processes, like loading apps, browsing the internet, streaming, and gaming.

SDRAM has the speed to switch quickly and efficiently between multiple tasks for maximum utility of your device. Data can be pulled from the long-term storage (ROM) and made available in RAM so it can be accessed without extensive searching.

The random access capability means that SDRAM can get to any area of data within the module equally fast. Its proximity to and intimate connectivity with the processor enables tasks to be actioned almost instantaneously. 

Does SDRAM Need to Be Upgraded?

SDRAM is the most common form of RAM in contemporary computing, so it is likely that your existing RAM is already SDRAM.

To upgrade SDRAM, you need to know what you are looking for. Here are some quick pointers:

• Establish the type of memory your computer currently uses via the manufacturer specification. Manufacturers usually install SDRAM as dual in-line memory modules (DIMMs) that hold the memory chips that make up a specified quantity of SDRAM.
• Find out how many pins the computer can accept (usually 184 pins or 240 pins for SDRAM).
• Look for a replacement memory module with enhanced speed and latency. Manufacturers measure SDRAM speed in MHz and latency in nanoseconds. Getting an SDRAM module with optimum speed and latency will significantly enhance the performance of your CPU. 
• If you install multiple SDRAM modules on your computer, ensure that they are identical. The voltage, speed, and even contact material should match. If they aren’t of equal speed, the computer will use the lowest speed.