今天几乎是被英伟达Rubin CPX的这个新闻刷屏了，但白天太忙，晚上回来才有时间好好看一下 SemiAnalysis的这个报告。在文章后半段，我们会简单分析一下Rubin CPX利好的两个方向。 AI 推理的两难困境 想明白 Rubin CPX 的价值，得先知道 AI 大模型推理时的一个关键矛盾： 预填充（prefill）和解码 （decode）这两个阶段，对硬件的需求完全是反的 。 在我们之前的一次分析华为的Cloud Matrix 384中光模块用量的直播中，讲到过Prefill和Decode的区 别： 在Prefill阶段特别吃计算能力，但对内存带宽的需求很低；而接下来的Decode，模型要基于第一个 token 不断生成后续内容，这时候就不怎么需要计算了，反而得靠高内存带宽快速调取之前的 KV 缓 存数据。 过去的问题是，大家都用同一种 GPU（比如英伟达的 R200）跑这两个阶段。结果在跑预填充时， R200 上那些昂贵的 HBM 内存（高带宽、高成本）根本用不上，带宽利用率较低，相当于花大价钱 买了个顶配跑车，结果只用来买菜；跑解码时，又觉得计算能力过剩，内存带宽不够用。这种通用 的硬件方案，不 ...

Investment Rating - The industry investment rating is "Outperform" [1] Core Insights - The report highlights the rapid development of large models and the acceleration of multimodal applications, with closed-source models gradually regaining an advantage over open-source ones [2][4] Summary by Sections Large Models - The development of multimodal technology is still evolving, with both domestic and international major players continuously refreshing state-of-the-art (SOAT) benchmarks [4][11] - Closed-source models are beginning to maintain performance advantages after the open-source wave, with significant advancements in video and image generation capabilities [4][19] Computing Power - Capital expenditures (Capex) from major cloud service providers (CSPs) are increasing, with chip manufacturers accelerating the release of new versions of chips [29][32] - Major CSPs like Microsoft, Google, Meta, and Amazon have raised their Capex guidance, indicating a strong focus on AI infrastructure [32][35] Applications - There is a noticeable acceleration in application differentiation overseas, particularly in complex B2B scenarios that integrate with data [47][64] - Companies that effectively leverage AI to enhance their core business operations are seeing significant revenue growth, particularly in the B2B sector [47][56]

Core Viewpoint - The HBM (High Bandwidth Memory) market is expected to experience tight supply and demand until 2027, driven by technological iterations and AI demand, with SK Hynix and Micron leading the market due to their technological and capacity advantages [1][2]. Supply and Demand Trends - HBM supply tightness is projected to persist through 2027, with a gradual easing of oversupply expected in 2026-2027. Channel inventory is anticipated to increase by 1-2 weeks, reaching a healthy level [2]. - The delay in Samsung's HBM certification and the strong demand growth from NVIDIA's Rubin GPU are the main factors contributing to the current supply-demand tension [2]. - HBM4 supply is expected to significantly increase by 2026, accounting for 30% of total bit supply, with HBM4 and HBM4E combined expected to exceed 70% by 2027 [2]. Demand Drivers - HBM bit demand is forecasted to accelerate again in 2027, primarily driven by the Vera Rubin GPU and AMD MI400 [3]. - From 2024 to 2027, the CAGR for bit demand from ASICs, NVIDIA, and AMD is projected to exceed 50%, with NVIDIA expected to dominate demand growth [3]. - Sovereign AI demand is emerging as a key structural driver, with various countries investing heavily in national AI infrastructure to ensure data sovereignty and security [3]. Pricing and Cost Structure - Recent discussions around HBM pricing are influenced by Samsung's aggressive pricing strategy to capture market share in HBM3E and HBM4 [4]. - HBM4 is expected to have a price premium of 30-40% over HBM3E12Hi to compensate for higher costs, with logic chip costs being a significant factor [4]. Market Landscape - SK Hynix is expected to lead the HBM market, while Micron is likely to gain market share due to its capacity expansion efforts in Taiwan and Singapore [5]. - Micron's HBM revenue grew by 50% quarter-over-quarter, with a revenue run rate of $1.5 billion, indicating a stronger revenue-capacity conversion trend compared to Samsung [6]. Industry Impact - HBM is driving the DRAM industry into a five-year upcycle, with HBM expected to account for 19% of DRAM revenue in 2024 and 56% by 2030 [7]. - The average selling price (ASP) of DRAM is projected to grow at a CAGR of 3% from 2025 to 2030, primarily driven by the increasing sales proportion of HBM [7]. - Capital expenditures for HBM are expected to continue growing, as memory manufacturers focus on expanding capacity to meet rising HBM demand [7].

Group 1: AMD's Market Position and Stock Performance - AMD's stock rose nearly 7% during recent trading and approximately 15% year-to-date, driven by growing investor confidence in its role in the AI chip market [2] - The AI semiconductor industry is expanding rapidly, with Nvidia dominating the market and more than doubling its revenue over the last two years, while AMD focuses on increasing GPU sales rather than surpassing Nvidia [2][3] Group 2: AI Market Dynamics - The AI market has seen significant investments from major tech companies, focusing on performance and training speed for large language models, which has favored Nvidia due to its leading chips and established ecosystem [3] - There is a potential plateau in the rapid enhancements of frontier AI models, leading to a shift towards inference workloads where efficiency and cost become more critical [3] Group 3: Opportunities for AMD - AMD may benefit as not all organizations can afford Nvidia's premium GPUs, leading some to opt for older Nvidia models or AMD's more budget-friendly MI series, which are suitable for inference tasks [4] - The introduction of open-source models like Llama from Meta could enable companies to run AI workloads on-site, reducing reliance on expensive cloud computing, which may also favor AMD [4] Group 4: AMD's Product Developments - At its AI Day event, AMD announced the MI350 series, launching in the second half of 2025, which promises four times the AI compute capacity of its predecessor, along with previews of the MI400 and MI450 chips [5] - AMD is enhancing its AI software and systems stack through acquisitions, positioning itself as a comprehensive AI provider, contrasting with Nvidia's proprietary environment [5] Group 5: Strategic Partnerships - AMD's partnership with Oracle aims to make its MI355X GPUs available through Oracle Cloud Infrastructure, offering over two times the price-performance advantage for large-scale AI tasks [6] Group 6: Competitive Landscape - Cloud providers like Google and Amazon are developing their own custom AI chips, which may limit long-term demand for third-party hardware solutions, while Nvidia may focus on more efficient mid-tier chips as the market shifts [6][7]