The Evolution of Memory Technology: Understanding GDDR5 and HBM2
In recent years, the world of computer hardware has witnessed significant advancements in memory technology. Among these developments, two notable types have emerged: GDDR5 (Graphics Double Data Rate 5) and HBM2 (High-Bandwidth Memory 2). In this article, we will delve into the specifics of these technologies, their differences, and the benefits they offer.
GDDR5 X: The Quad Data Rate Signaling Module
GDDR5 X is a variation of the GDDR5 technology. It utilizes quad data rate signaling, which should actually be referred to as GQDR 5. This alteration is not as costly as HBM integration. In a nutshell, GDDR5 modules are physically scattered around the graphics processor. The DRAM dies are extremely close to the GPU, and in some cases, they are even on the package itself. The controller stacks atop these DRAM dies to form an HBM module.
Each HBM module boasts 8 channels at 128 times 8 equals 1024 bits. Assuming a graphics card has 4 HBM modules, the memory bus of the card is 4096 bits, providing cards with HBM and insane memory bandwidth. This is significantly more than what GDDR5 can offer.
HBM2: A Costly but Rewarding Technology
HBM2, on the other hand, is a more costly technology that offers even higher memory bandwidth. It features quad data rate signaling as well but has undergone significant modifications to achieve this. HBM dyes are extremely close to the GPU, while DRAM dyes are stacked atop a controller to form an HB module.
Each module in HBM2 provides 1024 data links, assuming 4 stack DRAM dies per module, each with 2 128 channels per die. Every HBM module boasts 8 channels at 128 times 8 equals 1024 bits. If the graphics card in question has 4 HBM modules, then the memory bus of the card is 4096 bits.
This provides cards with HBM and insane memory bandwidth. However, HBM2 doubles the pin transfer rate of HBM1 and also allows for much more storage per unit. In comparison, the R9 Fury's HBM1 was limited to 1 gigabyte per stack, resulting in a maximum card size of 4 gigabytes.
AMD's Vega 56: A Case Study
To understand the benefits of HBM2, we can use AMD's Vega 56 as an example. The arbitrary numbers can get kind of confusing, so it's essential to review the variables involved in calculating memory bandwidth. The equation itself is very simple but the terminology can be quite confusing.
For Vega 56, the base clock speed is 800 megahertz, and the memory bus width is 2048 bits divided by 8, resulting in a memory bandwidth of roughly 410 gigabytes per second. By increasing the clock speed to 945 megahertz, the memory bandwidth jumps up to approximately 484 gigabytes per second.
The primary benefits of HBM2 are rooted in power and frequency optimizations. Since memory pathways are extremely short, power consumption is lower than that for GDDR5. However, this is not the full story. Each bus can operate at much lower frequencies while maintaining comparable or even higher memory bandwidth than GDDR5 counterparts.
Lower frequency equals lower input voltage, which also contributes to the efficiency parameter of HBM2. Printed circuit boards are much cheaper by comparison, making HBM less feasible for mass production. This is one of the reasons why GDDR5 has been so prevalent in recent years.
The Viability of HBM2
While cards with HBM typically result in smaller form factors and marginally lower power consumption, this is not the case with Vega 56. Both GDDR5 and HBM provide sufficient bandwidth for gaming, making it difficult to tell the difference in most scenarios.
However, the real benefit of HBM2 lies in its small design, which makes it particularly useful for VR applications. This technology has the potential to revolutionize the field of computer graphics and offer unparalleled performance.
Conclusion
In conclusion, GDDR5 and HBM2 are two distinct technologies that have evolved significantly over time. While GDDR5 remains a popular choice due to its affordability, HBM2 offers even higher memory bandwidth and power efficiency. Understanding these technologies is essential for appreciating the advancements in computer hardware.
The Future of Memory Technology
As researchers continue to explore new technologies, it's exciting to think about what the future holds for memory technology. Will we see further innovations like HBM3 or GDDR6? Only time will tell, but one thing is certain – the world of computer hardware is constantly evolving, and advancements in memory technology are at the heart of these changes.
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