Growing HBM4 stack demand supports AMD's 2027 AI chip roadmap

Daishin Securities: HBM > CSPs & AI Labs: Plans to develop lower-stack HBM products (4-high and 6-high) for low-end inference have been shelved, re-establishing 8-high HBM as the minimum stack height. > Nvidia: Dropped the 8-high option for Rubin due to supply constraints and customer demand for higher bandwidth over cost savings. For Rubin Ultra (2027), initial versions will use 8-high HBM4, while later versions will transition to 8-high or 12-high HBM4E. > AMD: Planning a mix of 8-high and 12-high HBM4 for 2027 products. Its upcoming MI450 chip will feature 12 HBM stacks per CoWoS package (delivering 288GB of HBM4), signaling growing medium- to long-term HBM content. > OpenAI & Anthropic: OpenAI is expected to adopt 12-high HBM4, whereas Anthropic plans to use 8-high HBM4. $AMD $NVDA $GOOGL $META $MSFT $AMZN