Nvidia’s Blackwell and Memory Bandwidth: Might Concern Mid-Range GPUs Again in 2025

Nvidia, a prominent player in the GPU market, is reportedly adhering to a 384-bit GDDR7 memory for its forthcoming Blackwell architecture. This decision has sparked a conversation among tech enthusiasts, particularly about the implications for mid-range GPUs and their memory bandwidth. This article provides a comprehensive analysis of Nvidia’s memory choices and their potential impact.

Yeah bois, 128-bit is coming for 70-series GPU’s again.

Nvidia’s Blackwell Architecture

The Blackwell architecture is Nvidia’s next-generation GPU technology, set to succeed the Ada Lovelace series. The flagship Blackwell GPU, known as GB202, is expected to maintain a 384-bit memory bus, similar to its predecessor. However, the significant change lies in the transition from GDDR6X to GDDR7 memory.

GDDR7 memory, with its higher data transfer rates and architectural peculiarities, promises to significantly enhance performance compared to existing GDDR6 and GDDR6X-based memory solutions. With the 1st Generation GDDR7 SGRAM ICs featuring a data transfer rate of 32 GT/s, a 384-bit memory subsystem using these chips would offer around 1,536 GB/s of bandwidth.

Mid-range GPUs and Memory Bandwidth

The memory bandwidth of mid-range GPUs has been a topic of interest, especially in light of the transition from Ada Lovelace to Blackwell. The Ada Lovelace architecture, for instance, used a 256-bit memory bus for its mid-range AD104 GPU. It was a departure from previous generations, which typically featured a 256-bit memory bus.

Despite the increase in bandwidth due to the shift to GDDR7 memory, concerns have been raised about whether this will be sufficient for mid-range GPUs. The argument is that while the bandwidth increase is beneficial, it may not result in a significant performance boost for these GPUs.

The product range of NVIDIA GeForce RTX 40, also known as “Ada”, presently encompasses five distinct SKUs.

AD102 (384-bit)
AD103 (256-bit)
AD104 (192-bit)
AD106 (128-bit)
AD107 (128-bit)

Assuming NVIDIA opts for the standard 16 GB (2 GB) memory dies operating at 32 Gbps pin speeds, the lineup could potentially be as follows:

1. GB202
   • Memory Bus: 384-bit
   • Pin Speed: 32 Gbps
   • Max Memory: 24 GB
   • Max Bandwidth: 1536 GB/s
2. GB203
   • Memory Bus: 256-bit
   • Pin Speed: 32 Gbps
   • Max Memory: 16 GB
   • Max Bandwidth: 1024 GB/s
3. GB204
   • Memory Bus: 192-bit
   • Pin Speed: 32 Gbps
   • Max Memory: 12 GB
   • Max Bandwidth: 768.0 GB/s
4. GB206
   • Memory Bus: 128-bit
   • Pin Speed: 32 Gbps
   • Max Memory: 8 GB
   • Max Bandwidth: 512.0 GB/s
5. GB207
   • Memory Bus: 128-bit
   • Pin Speed: 32 Gbps
   • Max Memory: 8 GB
   • Max Bandwidth: 512.0 GB/s

Conclusion

While Nvidia’s decision to stick with a 384-bit GDDR7 memory for its Blackwell architecture is noteworthy, the implications for mid-range GPUs and their memory bandwidth are complex. Although the shift to GDDR7 memory will result in increased bandwidth, whether this translates to a noticeable performance improvement for mid-range GPUs remains to be seen. As always, real-world performance will ultimately depend on a variety of factors, including game optimization and driver support. Therefore, while speculations abound, the true impact of Nvidia’s memory choices will only become clear once the Blackwell GPUs are released and put to the test.

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Source: @kopite7kimi