/ˌdʒiː ˌdiː ˌdiː ˈɑːr fɔːr/
n. — “GDDR4 is the in-between graphics memory lane that tried to go faster before the big leap to GDDR5 took over.”
GDDR4 (Graphics Double Data Rate 4) is a generation of graphics DRAM that followed GDDR3 and preceded GDDR5, designed to push higher data rates and better power efficiency for dedicated graphics cards. Architecturally, GDDR4 refines techniques from earlier DDR-family memories and graphics-focused designs, aiming to increase per-pin bandwidth through higher effective clock speeds and more aggressive signaling. In practice, adoption of GDDR4 was relatively limited because the industry moved quickly toward the higher performance and broader ecosystem support of GDDR5.
Key characteristics and concepts include:
- Higher potential data rates than GDDR3, achieved by tightening timing parameters and improving the I/O interface to support faster edge transitions and more efficient burst transfers.
- A design focus on balancing bandwidth gains with improved power characteristics, attempting to reduce energy per bit transferred compared with earlier graphics memory generations.
- Use primarily on a narrower set of mid-to-high-end graphics products during its window of relevance, as vendors evaluated the cost, complexity, and ecosystem benefits relative to jumping directly to GDDR5.
- Compatibility considerations that kept the basic graphics-memory usage model similar to GDDR3, with wide buses and burst-oriented access patterns feeding parallel shader arrays on a dedicated graphics processor.
In a typical rendering workflow, a GPU equipped with GDDR4 still streams large blocks of geometry, textures, and render targets as wide, sequential bursts rather than small random reads, relying on the higher effective data rate to keep shader cores busy. The memory controller aggregates requests from parallel execution units into aligned bursts that saturate the available GDDR4 channels, which can improve frame rates or enable higher resolutions and quality settings compared with similar designs limited to GDDR3, as long as the rest of the pipeline is balanced.
An intuition anchor is to picture GDDR4 as a short-lived, upgraded highway: faster and a bit more efficient than the older GDDR3 road, but soon overshadowed by the much larger, higher-speed expressway that GDDR5 eventually provided for graphics workloads.