Analyst Accuses SanDisk of Misrepresenting HBM Performance
Zephyr claims a SanDisk chart misrepresents HBM performance against HBF for Qwen3-480B.
Zephyr shared a SanDisk chart comparing an HBF-based xPU to a traditional HBM setup running Qwen3-480B. In a follow-up post the analyst stated the chart misrepresents HBM by fixing bandwidth at 1.6TB/s for both stacks and assuming bf16 weights. Zephyr noted that current models run on fp4 or fp8, requiring 240GB to 480GB for Qwen 480B depending on quantization. Gavin Baker replied that literally no one uses bf16 anymore and called the comparison funny.
SanDisk could only pull off this finesse in front of finance bros on "Investor Day"
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Analyst Accuses SanDisk of Misrepresenting HBM Performance
Zephyr claims a SanDisk chart misrepresents HBM performance against HBF for Qwen3-480B.
Zephyr shared a SanDisk chart comparing an HBF-based xPU to a traditional HBM setup running Qwen3-480B. In a follow-up post the analyst stated the chart misrepresents HBM by fixing bandwidth at 1.6TB/s for both stacks and assuming bf16 weights. Zephyr noted that current models run on fp4 or fp8, requiring 240GB to 480GB for Qwen 480B depending on quantization. Gavin Baker replied that literally no one uses bf16 anymore and called the comparison funny.
SanDisk could only pull off this finesse in front of finance bros on "Investor Day"
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2 postsZE 
Zephyr@zephyr_z9They are deliberately misrepresenting HBM performance For some reason, they fix the bandwidth of both HBM & HBF stacks at 1.6TB/s (12.8/8) Secondly, nobody serves models on bf16 anymore Most models are served on fp4 or fp8 So a Qwen 480B should occupy 240GB to 480GB depending on…
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GB Gavin Baker@GavinSBaker@zephyr_z9 Kinda funny. And yes, literally no one uses bf16 anymore.
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