Hi. This is probably an odd request, but my current laptop taught me that listening to music through headphones from a machine that makes noise, even low-level noise, is terrible. So I want to replace it with something newer and higher-level, but I'm worried very few laptops, if any, satisfy this requirement.
Will I have to limit my search by models with only integrated graphics core? I know many laptops allow programmatic control of the CPU fan so I can just set it to 0, but I did not find a way to control the speed of the GPU fan - that's what's killing me in my current laptop. Are there laptops that can stop the GPU fan entirely when the GPU is not in use?
Nope, not really. Unless you go with Intel laptops that have CPUs that are less powerful than a Core i3. An idle dedicated GPU generally does not draw much power, but I assume the fan is spinning slowly to cool it down as a precaution. CPUs are at least somewhat active even at idle, because of background Windows processes. "U" model Core CPUs only have 2 cores, but I would say that most people who wants to buy a gaming laptop wants a quad core CPU which can run relatively hot, therefore the fan is always running even if is spinning slow. Again, this is a precaution because if the fan stops, it opens up a liability to the manufacturer for warranty service which costs them money.
The only laptop that I am aware of that has at least a Core i3 CPU and is 100% silent is the 12" Acer Switch 12 Alpha convertible laptop. It is basically a Surface Pro 4 clone. It uses liquid cooling to cool a dual core Core i3 /i5/i7 CPU. It does not have dedicate graphics.
Your only other alternative is to buy headphones with passive sound isolation or active noise cancellation. The former would be the cheaper alternative.
Passive sound isolation could be earbud headphones which provides a good seal for your ears and are not expensive. You can also buy over the ears headphones where the headphone cups are larger than your ears and should provide good sound isolation. Active noise cancellation headphones are the more expensive route, but are generally less the cost of an average Core i3 laptop.
Headphones that are geared towards audiophile can be expensive though especially over the ear and active noise cancellation version costing more than the average Core i5 laptop.