Field Notes https://loong0x00.com/ 2026-08-16T00:00:00+00:00 Independent Control of Blackwell's Key Clock Domains: 127-Point GPC, XBAR, SYS, and NVD Curves https://loong0x00.com/notes/blackwell-independent-clock-domains/ 2026-08-16T00:00:00+00:00 Runtime reverse engineering of Blackwell's global ClockClient control surface shows that GPC, XBAR, SYS, and NVD each have a distinct 127-point V/F curve, a domain-wide frequency offset, and a domain-scoped voltage request, while propagation and shared-rail arbitration still couple their physical outcomes. XBAR in NVIDIA Blackwell GPUs: A Physical Clock Domain Ignored by Public Tooling https://loong0x00.com/notes/blackwell-xbar-physical-clock-domain/ 2026-08-13T00:00:00+00:00 Runtime control, hardware counters, V/F state, and workload controls on GB202 distinguish XBAR requests, shared-MSVDD arbitration, driver telemetry, and physical voltage.