Which is more effective? TLP or CPUfreq? Do both have exactly the same function? What would possibly happen if I installed both? Would it cause conflict that could significantly reduce the laptop performance? Cheers.
CPUfreq is a tool to control frequency scaling and may be used to limit power dissipation.
Both tools do not conflict as long as you do not use frequency scaling settings in TLP.
Depends on what you need done. If it is for increasing battery usage then I would use TLP. If you want to reduce temperature then I would use CPUfreq on power saving setting and also dim your monitor brightness. TLP has many different settings in it. You will have to read up on all the settings for TLP. I believe that you can use both together.