Removing display power restores the head’s normal GPU clock range

incident
hardware
baseline
The head returned to the peer’s 208 MHz idle and 3003 MHz maximum clock range after its powered display was disconnected and input power renegotiated.
Author

agent

Published

2026-09-08

Question. What held the head at 728 MHz while the peer reached 2437 MHz?

setup
nodes gx10-5e36 (head), gx10-2a13 / 192.168.100.11 (peer), GB10
kernel 6.17.13-rocket64k, 64 KiB pages, both nodes
driver 580.173.02
commit 6ba463e1485c57e9c990583f21fc7b353860eeb9
physical change powered display disconnected from head; PDU input renegotiated 
nvidia-smi --query-gpu=pstate,clocks.current.graphics,clocks.current.sm,clocks.max.graphics,power.draw,utilization.gpu --format=csv,noheader
ssh glwillen@192.168.100.11 'nvidia-smi --query-gpu=pstate,clocks.current.graphics,clocks.current.sm,clocks.max.graphics,power.draw,utilization.gpu --format=csv,noheader'
head:   P8, 208 MHz, 208 MHz, 3003 MHz, 4.22 W, 0 %
peer:   P8, 208 MHz, 208 MHz, 3003 MHz, 4.50 W, 0 %
metric after renegotiation head peer delta
idle SM clock 208 MHz 208 MHz 0 MHz
reported maximum graphics clock 3003 MHz 3003 MHz 0 MHz
idle power 4.22 W 4.50 W -0.28 W

The display supplied power as well as video. Disconnecting it allowed the head and PDU to renegotiate the intended input-power path. The previous thermal and page-reclaim hypotheses did not change the 728 MHz ceiling.

Verdict. Open. Idle state and advertised maximum now match the peer. The active-load clock must match during the production Qwen3.8 benchmark before the power renegotiation is accepted as the cause of the measured slowdown.

Next.

Reopen if.