Yes, definitely! Your laptop is generally constrained by how much heat it can push through the heat sink. If you get "lucky" you have a CPU that can remain stable at lower voltages. So it's effectively the same as an "overclock" because your laptop can turbo the core speed up for longer (or forever). Your laptop rarely runs at maximum turbo all day. It can only do that for a few hundred ms usually. It'll basically just hold the clock speed at whatever it can before hitting some specific temp (85-95c). When you undervolt, the frequency that it can "hold" at that temp threshold is higher.

Of course it does. Undervolting is simply finding the lowest voltage your unit can stably work at.

The only result of undervolting on modern CPUs is lower temperature; performance actually goes up as the processor still aims to hit its set TDP/TPL limits.

Lower voltage = higher clocks for longer on all Intel CPUs that can be undervolted. I believe it's the same for new AMDs, but I haven't had the chance to test one.

You're basically fine tuning your pet rock - some silicon is higher quality and can do better than the stock voltages that were set for thousands/millions of units out of the factory.

Might avoid hitting a thermal threshold and downclocking.

IME on most portable computers it's heat dissipation that's giving you the upper bound on clock speed not the CPU's actual upper bound.

A lot of laptops are built with pretty lack luster thermal design.

Less voltage means less waste heat. If you can lower voltage without lowering clock speed, you'll be able to maintain turbo boost longer instead of constantly thermal throttling.

Not my first recommendation but it is a valid strategy.

It helps a bit to reduce power/thermal throttling, from my experience the effect is not very strong though (maybe 5-10 % at most I'd say). If your CPU gets thermally throttled a lot it's more likely that you have a faulty or underdimensioned heat sink, in that case I'd try to apply better thermal paste and/or ensure the heat sink properly connects to the CPU. My Alienware throttled the CPU a lot due to overheating because they didn't apply the thermal compound right during fabrication (and seemed to use cheap compound with low conductivity), applying better thermal compound fixed that problem reliably, while undervolting the CPU did almost nothing in that case.

Voltage is an energy gap between on and off state of the transistor. There is also random noise on top of that gap. And that noise can sometimes cause the transistor to flip randomly, which results in an error. More voltage means system is more stable and has less random errors. But in gaming people often don't care if there is an error or two now and then, so they can tradeoff stability for lower power usage. Companies don't like that, because that means more technical support when programs randomly crash.

Many computers, especially those fan less laptop/2-in-1 tablet, doesn't have adequate cooling system.

If CPU was used too much, it instantly reach the temperature threshold, then forced down clock and stall kicks in to save the CPU, repeat the cycle.

Which way do you prefer? endless cycle of 60fps for 10 seconds followed by shuttering for 10 seconds, OR stable 20fps.

of course it does - less voltage => more power headroom and less overall power, less heat dissipated => more thermal headroom.

If the silicon doesn't need the voltage, more voltage is only harmful. I can run my skylake alike laptop at -170mV offset (which is borderline golden chip), stable at prime 95 and whatnot. Prime95 runs below 70C.

hmm maybe less thermal throttling?