Is my new laptop faulty or is the hardware just not up to scratch?

I bought a HP 15, WIndows 10 laptop last week. It has an AMD 9 CPU, 4GB of RAM, 1 TB HDD and a Radeon R5 GPU.

My expectations were low as I know it's a fairly basic system, but It literally struggles to browse the web and is VERY laggy. I've tried dozens of things to speed it up i.e cutting bloatware loose, limiting start-up processes, maximising performance etc. Nothing seems to help. I'm thinking about expanding the RAM and getting an SSD installed, but my CPU seems to always be maxed out anyway, so not sure this will help? Thanks ins advance.