What’s the Difference Between DDR and GDDR Memory?

Modern graphics cards generally use a form of GDDR memory as VRAM, with GDDR5, GDDR5X, and GDDR6 being the common standards in 2020. System RAM generally uses DDR4 memory although older computers will still be found with DDR3 RAM.

Tip: DDR stands for Double Data Rate, while the G in GDDR stands for Graphics.

What is RAM?

RAM or Random-Access Memory, is a form of memory placed between the long term memory (SSD or HDD) and the processor. RAM, or VRAM (Video RAM) in the case of graphics cards, is essentially used to cache data so that it can be accessed faster, reducing how long the processor has to wait for the data it needs to perform calculations.

You don’t require a specific version of VRAM to work with any version of RAM, or vice-versa, as the two memory types are exclusively used by their respective processors.

What are the use cases for RAM vs VRAM?

Both DDR RAM and GDDR VRAM are optimised for the specific type of tasks that they are designed to perform. For example, system RAM is designed for extremely low latency, so small bits of data can be accessed as fast as possible.

In comparison, VRAM is primarily designed to move very large amounts of data. This is because the two most common graphics card workloads are graphics rendering, that uses high-resolution textures, and computer simulations, which have huge data sets. As such VRAM has a much wider memory bus which allows for much greater bandwidth.

So, while the exact differences between each generation of DDR and GDDR memory vary, the main difference is that they prioritise a different metric. DDR memory, prioritises low latency, whereas GDDR prioritises high-bandwidth.

Tip: It may sound that GDDR5 VRAM is a generation ahead of DDR4 RAM, however, this isn’t actually the case. The two technologies progress independently of each other. GDDR5 is more closely related to DDR3 than it is to DDR4.