CPU & Global performance problems

Hello !

I'm building an ELK system for log analyse but i'm facing a new problem. My kibana crash very often (timeout 30000ms) and when i check my running process i can see that ES takes between 50 and 400% of the cpu.

Does ES have some expensive hardware requirement (ATM the system is running on a 4 core cpu (@3.6GHz) and 8GB of RAM) or it's just some conf problems ? in this case can you help me to solve this problem ?

also, i have around 100k data per hour, so not that much comparing to other ELK system.

Thanks for the attention.