相同的硅，不同的产品
HBM（高带宽内存）通过硅通孔堆叠 8 到 16 个 DRAM 芯片，并将它们粘合在 GPU 或 ASIC 旁边。 DDR5 和 DDR4 是销售给服务器、PC 和模块的单芯片。两者都是从相同的三个供应商生产 DRAM 晶圆，因此它们争夺相同的晶圆厂产能。
HBM 按多季度分配方式出售给少数加速器买家。 DDR5 和 DDR4 在合约和开放现货板上进行交易。这就是为什么这里的 HBM 水平被标记为报告或源自供应链报告，而 DDR5 则带有每日现货打印。
当今主板上的每 GB 成本
HBM3 24GB: $8.31/GB. HBM3E 36GB: $58.56/GB. HBM4 48GB: $73.35/GB. DDR5 16Gb: $29.27/GB. DDR4 16Gb: $41.48/GB. GDDR6 16Gb: $5.81/GB.
These per-GB figures are derived: the published level divided by the part's capacity. The HBM3E and HBM4 levels are scarce-lot spot indications reported in September 2026, several times long-term-agreement pricing, so contract buyers pay materially less per GB than this line suggests. Read the HBM per-GB number as a ceiling, not a typical cost.
为何 HBM 需求推高 DRAM 价格
一旦计算出堆叠良率和较大芯片，每个 HBM 位使用的晶圆面积大约是 DDR5 位的三倍。每一块转移到 HBM 的晶圆都会从商品市场上去除数倍于 HBM 产量的晶圆。供应商一直在转移晶圆，因为 HBM 利润率更高，这是 2025-26 DDR5 和 DDR4 挤压的核心。
该图表将每行的基数重新设置为 100，以便您可以看到哪一部分先移动。在更长的时间内，商品线的变动比 HBM 更远：HBM 的定价提前一年进行分配，而现货 DRAM 在每个交易日都会重新定价。
什么会缩小或扩大差距
Downside first: consumer DRAM demand is soft under current prices, and DDR5 spot inquiries have slowed in September. If spot DRAM stalls while HBM allocation holds, the HBM-to-DDR5 ratio widens again. Extra HBM4 capacity at SK hynix, Samsung and Micron could also ease the scarce-lot HBM premium through 2027.
Upside: any accelerator build-out beyond current allocation keeps converting wafers and holds commodity DRAM tight. Watch a sustained negative 30-day print on HBM3, the oldest generation, as the first sign HBM pricing is softening.