Nvidia's Kyber GPU racks will feature 340.4 TB of HBM, with HBM4E priced at $19.76/GB and complete racks at $41.6 million each.

NVIDIA's upcoming Vera Rubin Ultra systems face persistent rumors of potential HBM de-specification as the company looks to preserve margins. Bank of America recently released an analysis quantifying the dynamics between HBM4E and LPDDR5X-based SOCAMM2 modules within these new Vera Rubin Ultra-based Kyber racks.

Each base Rubin GPU currently includes 288 GB of HBM4 across 8 stacks, delivering up to 22 TB/s of bandwidth per GPU. The Vera CPU, meanwhile, abandons standard server RDIMMs in favor of LPDDR5X-based SOCAMM2 modules—which use a compression connector that sits flat against the motherboard to shorten electrical traces, giving LPDDR5X the signal integrity and low latency required for data center operations. Each Vera CPU features 8 SOCAMM2 slots, providing a theoretical memory capacity of 1.5 TB of LPDDR5X per CPU via 192 GB modules.

According to Bank of America, HBM4E costs $19.76 per gigabyte. Each 144-GPU Kyber rack will contain 216 TB of LPDDR5X at approximately $2.8 million, paired with 124.4 TB of HBM4E costing around $2.5 million. The total price per Kyber rack reaches $41.6 million. BofA notes that despite rising HBM capacity and pricing, HBM remains a relatively modest component of rack economics at 5–6% of value, compared to 7.5% in Blackwell Ultra systems.

UBS estimates each Rubin GPU within the Vera Rubin superchip configuration costs $9,247, including HBM4, packaging, interposer, and peripherals. Each Vera CPU costs approximately $20,059 including SOCAMM2 LPDDR5X, plus $350 for other board components. DRAM accounts for roughly half of GPU costs and nearly all CPU costs (which amount to just $704 after removing memory).

Compared to Blackwell servers—where Grace CPUs had 480 GB of memory and Blackwell GPUs offered 192 GB (GB200) or up to 288 GB (GB300) of HBM3E—the memory pool has expanded substantially. Vera Rubin racks contain 74.7 TB of total memory across HBM4 and SOCAMM2. For Kyber racks, this capacity balloons to 340.4 TB.