Laptop RAM and APU's

So my knowledge of Laptops are a little off. My girlfriend has a laptop (HP Pavilion 15z) that she is giving to her little brother. He plays games like Minecraft and some other small indie games. I know that faster RAM in a desktop APU improves the frame rate but does it in this laptop's APU? I have an 8gb kit of 1866mhz, if I were to put that in there would it help his fps?

Yep. Laptop APUs have the same limitations as desktop APUs in that they don't have onboard GDDR5 like dedicated graphics cards so they have to share desktop memory with the CPU. Faster speeds on memory really do help a lot with framerates on GPUs.

Disclaimer because I'm not familiar with your technical knowlege/don't be offended: Laptop memory and desktop memory have different form factors so make sure it's the laptop (SO-DIMM i believe is the name) form factor. Also, check the manufacturer's website to make sure they support that much RAM in the laptop, if it's pretty modern that won't be a problem but if it's several years old you may have an issue or two. Thirdly, make sure you have 64-bit windows otherwise half of that RAM won't be accessible.

Right I understand the spec requirements and stuff, I work on computers for a living but I haven't done a lot of work on a laptop in quite some time so I was just double checking stuff. Thanks!

Highly depends if the motherboard and BIOS allow it to run at 1866MHz.

It might just default to 1600 or even 1333.