Laptop not running on full performances after a short while

[ponlas]

So while playing League of Legends, my laptop can run it on around 100+ FPS with all settings maxed out. However, it drops down to 40 FPS after a short while. Normally, when it does not run in full performance, switching to power saving mode lowers my FPS from 100+ to 60+. But after it drops, switching to power saving mode DOES NOT drop FPS. What's happening? 

EDIT: I assume it's a processor cap? I'm unsure.

[chris635]

Sounds like your CPU is thermal throttling.   

[edkiefer]

yup, sounds like either thermal or TDP issue with CPU/GPU , you would need to monitor clocks speed and temps to see it .

[BenYeeHua]

It is overheat after you playing with performance(A.K.A full speed for CPU and GPU), then one of them or both get throttle by the BIOS.

And ya, it can also be a graphic card issues, if you switch to Power Save mode will switching from Nvidia/AMD graphic to Intel graphic.

[Jeremy Collake]

I agree with Chris, Ed, and Ben. Sounds a lot like thermal throttling.

If your CPU (or GPU) begins to overheat, it will self-throttle.

On a properly designed and maintained system, this shouldn't happen, but not everything in the world is properly done .

[BenYeeHua]

On a properly designed and maintained system, this shouldn't happen, but not everything in the world is properly done .

When you are testing it without thinking about the Summer, then yup.

Many high end laptop(or some old laptop that easier to overheat) are facing this problem, they found that most of the time, the graphic card or CPU will overheat and getting throttling under performance mode, and they need to disable the TurboBoost, so that it will not be throttled under Base Clock.

[ponlas]

Thanks guys, indeed my laptop's temperature had been over 80+ degrees while I was playing on full settings. That was pretty shocking lol. Anyway, what's the normal temperature of laptop? BTW is 70+ bad? I tuned down the settings and am running around 70+ degrees.

[Jeremy Collake]

Normal depends on the processor, varies a great deal... you should make sure your vents are dusted well and fans functioning, as, in theory, a properly built laptop should not overheat -- unless you have it overclocked(?)

[BenYeeHua]

It depend on the laptop, normal low end laptop that are more than 2 year ago will be 80°C and get throttle, for medium end laptop, they might just increased it to 90°, or lower it to 70° to reduce the risk for getting it damaged.

If your laptop get throttled, then it means it is not design to running at that temperature.