CPU and RAM frequency, maybe from the BIOS?. RAM amount I don’t know how.
For NVidia on Linux:
Which version of the nvidia driver you use? What brand and model is your card?
I’m using “352.21” in my GTX 960 I get the extra features in nvidia-settings with “Coolbits” “28” (as indicated in some forums):
But I do not know, you be careful and read what they say there on the second link about the number “28”. another link:
With the next command the configuration is written to /etc/X11/xorg.conf using “28”:
sudo nvidia-xconfig --cool-bits=28
Restart the system.
Now in nvidia-settings you have the options for the fan on Thermal Settings and frequencies in PowerMizer. You enter the desired value in the field, and press Enter.
You verify in the fields above that the frequencies are modified when you press the Enter key. I’ve noticed that if I have Blender open, there are times that the frequencies are not changed, and I must close Blender.
You be careful, put fan in high-speed and you monitor the temperature of the GPU all the time. I know you want underclock, but anyway.
By the way, in my GTX 960 ssc is possible reduce the frequency only -200 MHz