Nvidia CMP cards get memory clock locking: OneZeroMiner 1.8.5 and ForgeMiner 1.9.2 cut power at 405 MHz

Nvidia's display-less CMP mining cards can finally have their memory clock locked low under Linux. OneZeroMiner 1.8.5, released on November 4, 2026, added experimental memory locking at 5000, 810 and 405 MHz for the CMP 30HX, CMP 40HX, CMP 50HX, CMP 70HX and CMP 90HX, and the developer says it brings 20 to 50% better efficiency on all core algorithms, according to the release notes. Two days later ForgeMiner 1.9.2 shipped the same control for the CMP 90HX and CMP 50HX.

What changed

• OneZeroMiner 1.8.5: the --mclk option now sets 5000, 810 or 405 MHz on CMP 30HX to 90HX cards. The feature is experimental and so far has only been tested on HiveOS with Nvidia driver 610.43.03.
• The same release can lock memory at 405 MHz on RTX 20, 30, 40 and 50 series cards on Linux, with the core clock kept in its normal range. It was tested on drivers 595 and 610; 580 and older are not supported. The developer notes it does little for the RTX 50 series.
• ForgeMiner 1.9.2: --mclk 5000, 810 and 405 now hold on the CMP 90HX and CMP 50HX with driver 595 or newer, and the memory clock is put back as it was when the miner exits.

The measured effect on Pearl

ForgeMiner's developer tested 12 CMP 90HX cards mining Pearl at 405 MHz: power fell by about 27% while hashrate dropped by 1.6%. By our calculation from those two figures, energy per hash falls to about 74% of the stock level.

The gain is not universal. On RTX 30, 40 and 50 cards the same test saved at most 1.6 W per card for up to 0.9% less hashrate. Pearl on the RTX 20 series and on the CMP 50HX needs fast memory: at 810 MHz and below they lose most of their hashrate, so owners of those cards should keep memory high for Pearl.

What CMP owners should do

• Use Linux with Nvidia driver 595 or newer; the CMP locking in OneZeroMiner has so far only been checked on driver 610.43.03.
• Try 405 MHz on core-bound coins first, then compare wall power and accepted hashrate over a few hours rather than trusting the console alone.
• OneZeroMiner 1.8.5 also sends active GPU names to the pool when you mine Pearl; add --disable-pearlhash-telemetry if you want to opt out.