Nvidia reportedly testing lower memory configs of Rubin Ultra as memory shortage bites back — designs tested include as little as 192 GB and step back to HBM4

Nvidia's Rubin Ultra targets 768GB of HBM4E as Kyber platform stays on schedule

Nvidia Rubin Ultra targets 768GB HBM4E per GPU for H2 2027, down from 1TB to match SK Hynix/Samsung supply outlook. Tripled capacity (288GB→768GB) allows larger models per GPU, reducing inter-chip data transfers and training energy cost.