What's The Difference between High Bandwidth Memory (HBM) And DDR5 Chips in AI Servers?

High Bandwidth Memory (HBM) : Developed by the JEDEC Standards Organization, it is designed for high-performance computing and graphics processing. The main feature is stacking multiple layers of DRAM chips together through 3D stacking technology and vertical interconnection using through-silicon holes (TSV) to achieve high bandwidth and low power consumption.

DDR5 memory: The latest generation of double data rate synchronous dynamic random access memory (SDRAM). It is mainly used in personal computers, servers and mobile devices. Compared to previous generations of DDR memory, DDR5 offers higher speeds and greater chip density.

1. Speed

HBM: Typical data rates for HBM range from 1 Gbps to 2 Gbps. HBM2E (second Generation Enhanced) provides data rates up to 3.2 Gbps.

DDR5: The initial data rate range for DDR5 starts at 4.8 Gbps. Future high-end DDR5 modules may reach 6.4 Gbps or even higher.

3. Bandwidth

HBM: HBM achieves extremely high bandwidth through a wide bus and multi-layer stack. HBM2 provides a single stack bandwidth of up to 256 GB/s. HBM2E has a single stack bandwidth of up to 460 GB/s.

DDR5: DDR5 improves bandwidth with higher data rates and wider buses. The bandwidth of a single DDR5 memory is approximately 38.4 GB/s (based on a 4800 MHz rate). The multi-channel DDR5 configuration can further increase the total bandwidth.

4. Chip density

HBM: HBM uses 3D stacking technology to achieve high chip density. A single HBM stack can contain up to 8 layers of DRAM chips, each with a capacity of up to 2GB. The HBM2E stack can have a maximum capacity of 16GB (2GB per layer, a total of 8 layers).

DDR5: The capacity of DDR5 memory starts from 8GB, and usually a single memory can reach 32GB. With technological advances, the capacity of a single DDR5 memory bar may reach 64GB or even higher in the future.

5. Application Scenarios

HBM is primarily used for high-performance computing (HPC) applications that require high bandwidth and low latency. Commonly found in high-end graphics processors (Gpus), accelerators, and servers.

DDR5 is mainly used in a wide range of application scenarios that require large capacity and high data rates, such as personal computers, workstations, and servers. Widely used in a variety of consumer and enterprise equipment.DDR5