$ atitweak -l
0. ATI Radeon HD 5800 Series  (:0.0)
    engine clock range is 80 - 918MHz
    memory clock range is 150 - 1200MHz
    core voltage range is 0.95 - 1.088VDC
    performance level 0: engine clock 800MHz, memory clock 300MHz, core voltage 0.95VDC
    performance level 1: engine clock 918MHz, memory clock 300MHz, core voltage 1.088VDC
    performance level 2: engine clock 918MHz, memory clock 300MHz, core voltage 1.088VDC
    fan speed range: 0 - 100%,  800 - 5100 RPM
1. ATI Radeon HD 5800 Series  (:0.1)
    engine clock range is 80 - 918MHz
    memory clock range is 150 - 1200MHz
    core voltage range is 0.95 - 1.088VDC
    performance level 0: engine clock 800MHz, memory clock 300MHz, core voltage 0.95VDC
    performance level 1: engine clock 918MHz, memory clock 300MHz, core voltage 1.088VDC
    performance level 2: engine clock 918MHz, memory clock 300MHz, core voltage 1.088VDC

$ atitweak --set-memory-clock=300 --performance-level=2 --adapter=0
Setting performance level 2 on adapter 0: memory clock 300MHz

$ atitweak --set-fan-speed=100 --adapter=all

$ atitweak --status --adapter=0

0. ATI Radeon HD 5800 Series  (:0.0)
    engine clock 950MHz, memory clock 300MHz, core voltage 1.088VDC, performance level 2, utilization 99%
    fan speed 100% (3447 RPM) (user-defined)
    temperature 85.5 C

Usage: atitweak [options]

Options:
  -h, --help            show this help message and exit
  -l, --list-adapters   Lists all detected and supported display adapters.
  -s, --status          Shows current clock speeds, core voltage, utilization
                        and performance level.
  -e ENGINE_CLOCK, --set-engine-clock=ENGINE_CLOCK
                        Sets engine clock speed (in MHz) for the selected
                        performance levels on the selected adapters.
  -m MEMORY_CLOCK, --set-memory-clock=MEMORY_CLOCK
                        Sets memory clock speed (in MHz) for the selected
                        peformance levels on the selected adapters.
  -v CORE_VOLTAGE, --set-core-voltage=CORE_VOLTAGE
                        Sets core voltage level (in VDC) for the selected
                        performance levels on the selected adapters.
  -f FAN_SPEED, --set-fan-speed=FAN_SPEED
                        Sets the fan speed (in percent) for the selected
                        adapters.
  -d, --set-fan-speed-default
                        Resets the fan speed to its default setting.
  -A ADAPTERLIST, --adapter=ADAPTERLIST
                        Selects which adapters returned by --list-adapters
                        should be affected by other atitweak options.
                        ADAPTERLIST contains either a comma-seperated sequence
                        of the index numbers of the adapters to be affected or
                        else contains the keyword "all" to select all the
                        adapters. If --adapter is missing, all adapters will
                        be affected.
  -P PERFORMANCELEVELLIST, --performance-level=PERFORMANCELEVELLIST
                        Selects which performance levels returned by --list-
                        adapters should be affected by other atitweak options.
                        PERFORMANCELEVELLIST contains either a comma-separated
                        sequence of the index numbers of the performance
                        levels to be affected or else contains the keyword
                        "all" to select all performance levels. If
                        --performance-level is missing, all performance levels
                        will be affected.