It should be pretty small.
Basically the way to look at is that laptop screen typically operate at 60Hz which it gets refreshed 60 times per second and that translates to being capable of displaying a maximum of 60 FPS.
Each second is equal to 1000ms (milli-seconds). A screen that operates at 60Hz displays up to 60 FPS. That means each frame is displayed on the screen for 16.667ms. A screen with a 8ms response time means you will roughly get a half frame delay between doing an action with the keyboard/mouse or controller and when it is displayed on the screen. A screen with a 5ms response time means you will get slightly over 1/3rd frame delay. The higher the response time, the more likely you will see ghosting on the screen in fast action sequences as well.
In the past TN panels were favored in gaming laptops because they can have response times as low as 2ms. However, they have pretty bad viewing angles so when you are not looking direct the screen in front of you, then you can notice color shifting and color fading.
Over the last few years IPS panels (my preferred LCD panel tech especially for desktop monitors) have been gaining favor in gaming laptop. They were once scoffed at for it's relatively high response time. But now IPS panels are the preferred panel types to be used in mid range / high end laptops. Probably due to potentially better color reproduction, less color shifting and fading. IPS panels can have response times as low as 5ms.