Hardware control options

Here are some important notes about the hardware control options:

  • Most recent Nvidia drivers require running as administrator (or as root under Linux) to allow hardware control, so you must run PhoenixMiner as administrator for the VRAM timing options to work.

  • The AMD memory timing options (-rxboost, -vmr, -straps), with the notable exception of -mt, also require running as administrator (or as root under Linux)

  • When using the VRAM timing options (-straps, -vmt1, -vmt2, -vmt3, -vmr), start with lower values and make sure that the cards are stable before trying higher and more aggressive settings. You can use -straps along with the other options. For example -straps 1 -vmt1 60 will use the timings from 1st strap level but -vmt1 will be set to 60 instead of whatever value is specified by the 1st strap level. In such case the -straps option must be specified first.

  • Generally, the -vmt3 option has little effect on the hashrate, so first try adjusting the other parameters.

  • The VRAM timing options can be quite different between the GPUs, even when the GPUs are the same model. Therefore, you can (and probably should) specify the VRAM timing options per-GPU.

  • If you specify a single value (e.g. -cvddc 1150), it will be used on all cards. Specify different values for each card like this (separate with comma): -cvddc 1100,1100,1150,1120,1090 If the specified values are less than the number of GPUs, the rest of GPUs will use the default values.

  • We have tested only on relatively recent AMD GPUs (RX460/470/480/560/570/580/590, Vega, Radeon VII, RX5700, RX5500). Your results may vary with older GPUs.

  • The blockchain beta drivers from AMD show quite unstable results - often the voltages don’t stick at all or revert back to the default after some time. For best results use the newer drivers from AMD: 18.5.1 or later, where most of the bugs are fixed.

  • -tmax specifies the temperature at which the GPU should start to throttle (because the fans can’t keep up).

  • If you use other programs for hardware control, conflicts are possible and quite likely. Use something like GPU-Z to monitor the voltages, etc. MSI Afterburner also seems to behave OK (so you can use it to control the Nvidia cards while AMD cards are controller by PhoenixMiner).

  • This should be obvious but still: if given clocks/voltages are causing crashes/freezes/incorrect shares when set with third-party program, they will be just as much unstable when set via PhoenixMiner hardware control options.

  • If you have problems with hardware control options of PhoenixMiner and you were using something else to control clocks, fans, and voltages (MSI Aftrerburner, OverdriveNTool, etc.), which you were happy with, it is probably best to keep using it and ignore the hardware control options of PhoenixMiner (or use only some of them and continue tweaking the rest with your third-party tools).

  • In order to have working hardware control under Linux, you need relatively recent kernel (4.15 or later), recent AMD drivers (we tested with 19.30-855429), PhoeniMiner must be running as root (sudo ./PhoenixMiner), AND you need to add the following boot parameter to the Linux kernel: amdgpu.ppfeaturemask=0xffffffff

  • In all AMD Linux drivers there is a bug with returning the fan control back to automatic. As a workaround we added the parameter -fanidle which allows you to specify the default fan speed after PhoenixMiner is closed. The default value is 20%

  • In AMD Linux drivers the fan PWM curves are very strange and while we have tested on dozens of cards, and PhoenixMiner should be able to detect the PWM type automatically, you can use the -fpwm parameter to force different kinds of fan PWM mappings (not recommended unless you really know what you are doing).