How to disable 2 cores on a quadcore i7?

windows-7 multi-core cooling intel-core-i7

28,927

Solution 1

You can't command the processor to disable the cores, the only thing you can do to avoid the heat is going for another processor or to check that the processor is sufficiently cooled.

Solution 2

Many computers have BIOS options to disable cores. You can also disable hyper threading which is also disabling cores, though I doubt that would improve cooling much. A final thing that could be done is in Windows itself. Go to the Advanced Boot Options (msconfig > boot tab > Advanced options) and specify the number of cores you want to use. I would personally not recommend any of these solutions as it is basically castrating your machine. Find a better cooling solution or practice better usage of your machine such as using it only on hard surfaces, cleaning the dust out of the vents, using a cool pad, ect. You might also want to check for a BIOS update that will turn the fan on more often or use something like SpeedFan to manually control your fan speed and thus increase your cooling potential.

Solution 3

The Intel i series tends to do this. They have a certain thermal limit built in and basically manage the system such that: if you are running on all cores, it manages speed among them and tries to run the system as fast as it can without overheating. If you aren't running all cores, it will shut down the cores that aren't used and try to overclock the cores that are used - up to the thermal limit. Note that it TRIES to overclock and this creates heat.

Solution 4

In Linux/Ubuntu, just run this:

sudo sh -c "echo '0' > /sys/devices/system/cpu/cpu1/online"

Replace cpu1 with cpu2 and so on to turn off more cores. And to turn them back on:

sudo sh -c "echo '1' > /sys/devices/system/cpu/cpu1/online"

Solution 5

Go to Run, type in msconfig, go to Boot tab, click Advanced Options, and select "Number of Processors". Then change it to half of the list (Pick 4, because you have 8 threads = 4 cores, so 4 threads = cores). Reboot ;)

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28,927

royco

Updated on September 17, 2022

Comments

royco over 1 year

I have a laptop with a quadcore i7 that runs hot. I don't need 2 of the cores. How can I shut them off?
- JJ_Australia almost 14 years
  
  Why? (15 chars)
- Paul R almost 14 years
  
  What operating system ?
- squircle almost 14 years
  
  Maybe, maybe not. Either way, we need to know more about your laptop. What manufacturer/model is it?
- kobaltz almost 12 years
  
  More Cores <> More Heat, Higher CPU Usage = More Heat, Less Cores + CPU Intensive Task = More Heat, Same Cores + Better Ventilation = Less Heat, You may want to try and disable Hyper Threading in the BIOS if that's an option.
royco almost 14 years

Right, but is there a way to manually disable 2 cores? Turbo mode on this system never seems to turn on.
royco over 13 years

Thanks. I tried that originally. Even though this kept Windows from using additional cores, I'm pretty sure the cores were still on and consumed power.
Tamara Wijsman over 13 years

@mmmbacon: No, there is no way to disable them. Why would you spent a lot on a processor to downgrade the performance afterwards, I would rather fix the cooling instead.
Tamara Wijsman over 13 years

Sadly, this only affects the boot phase...
Tamara Wijsman over 13 years

Ah, in that way, sorry... Well, it's located under the boot tab so it only effects the boot phase. During which Windows detects all cores and from that point they should all be used instead of a single one. @mmmbacon confirms this in his comment, but interesting enough: I don't know about the effect towards device manager, they shouldn't disappear but I haven't checked...
Waldemar Wosiński over 7 years

Actually you can do it with core parking. Look for my answer.