Undervolting CPU, CPU Cache, iGPU and System Agent.

knowledge2121

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I have an i7-4800MQ, Out of CPU, CPU Cache, iGPU and System Agent, Which ones should I try to undervolt ?

Is it true that the most important ones are CPU and CPU Cache ? and that iGPU and System Agent make little to no difference ?
 

knowledge2121

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I haven't started yet, Just wanna know what I can do to reduce heat...My laptop has symptoms of overheating...and yes, i have cleaned the laptop, swapped the fan and applied new thermal paste too...
 

4745454b

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Cpu and igp will make the most difference, but will slow the laptop down the most as well. Is it thermal throttling? If you've cleaned it and checked the fans it should be working as it first came to you.
 

uWebb429

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...but will slow the laptop down the most as well.
Can you explain that? Reducing the CPU voltage does not slow a CPU down. The 4800MQ has a 47W TDP rating. Reducing the voltage reduces power consumption. This allows the CPU to use more turbo boost so it can run faster before triggering power limit throttling. Reducing voltage makes these CPUs run faster, not slower.

Is it true
Yes. The core and cache are the two most important voltages to tweak. They will give you the most bang for the buck. These two voltages do not have to be set equally. Use Cinebench R20 when adjusting your voltages.


Adjust all of the voltages and see what works best for your laptop.

The 4800MQ allows up to +4 bins (400 MHz) of overclocking as long as your laptop manufacturer did not lock this feature. Depending on what speed you decide to run your 4800MQ at, there might not be much room to reduce voltages before your CPU becomes unstable.
 
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4745454b

Titan
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Decreased voltage might also mean it doesn't have stability at XYZ frequency as well. Think of it as reverse overclocking. When you pump up the frequency you probably up the voltage as well. It works the same way in reverse. If you cut the voltage, you might have to drop the frequency. Every cop is different so you'll need to see where your chip works with XYZ voltage.

The only way it works like you say is if you tried to OC it and you pumped the voltage up to the max without increasing the cooling. I'm assuming that didn't happen.
 
Decreased voltage might also mean it doesn't have stability at XYZ frequency as well. Think of it as reverse overclocking. When you pump up the frequency you probably up the voltage as well. It works the same way in reverse. If you cut the voltage, you might have to drop the frequency.
With undervolting, you aren't trying to just find the lowest voltage the processor will run at period. You're trying to find the lowest voltage it'll run typically at stock frequency settings.
 

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