GDDR (Graphics Double Data Rate Memory) (originally known as DDR SGRAM – Double Data Rate Synchronous Graphics RAM) is a critical component in high-performance devices, especially in the graphics and AI fields.
The latest development in this technology is GDDR7, which Samsung first announced at Tech Day 2022. Although specific details were initially lacking, more information has since emerged about this promising new memory standard.
GDDR7 will be featured in the High Density Memory and Interfaces session at the 2024 IEEE International Solid-State Circuits Conference, which will be held for five days in February in San Francisco. There's not much to do at this point other than the Advanced Program's session heading: “16Gb 37 Gb/s GDDR7 DRAM with PAM3-Optimized TRX Equalization and ZQ Calibration.”
GDDR7 memory utilizes PAM3 and NRZ signaling and aims to achieve data rates as high as 37 Gbps per pin. That evolution involves increasing signaling speeds and burst sizes without significantly increasing the memory cells' internal clocks. This increases the memory bus frequency for each GDDR version, resulting in better performance.
However, as frequency increases become more complex, the industry is looking for other solutions. For example, GDDR6X replaced the traditional NRZ encoding with his PAM4 encoding, effectively doubling the data transmission speed. By lowering the baud rate, PAM4 also significantly reduces signal loss.
However, GDDR7 utilizes PAM3 encoding, which is a compromise between PAM4 and NRZ signaling. This provides higher data transfer rates per cycle than NRZ and reduces the need for higher memory bus frequencies. GDDR7 promises better performance than GDDR6 while offering lower power consumption and implementation cost than GDDR6X.
Additionally, GDDR7 provides ways to optimize memory efficiency and power consumption. It includes four different read clock modes and can be run only when needed. The GDDR7 memory subsystem can also issue two independent commands in parallel to optimize power consumption.
As for the release of GDDR7, it will likely be available later this year, along with next-generation GPUs from AMD and NVIDIA.