Help upgrade the gaming PC my brother gave me!

[BillyMA]

Hello,
My brother gave me his old gaming PC (spec below) and it works OK but it's a bit jerky and sometimes freezes for a little bit even with a local game. I have nearly £300 saved up and wondered what I could do to make it better. THANKS!!

Intel Core i7
Windows 10
1TB HD
2GB Nvidia GeForce GT1030

 

[BillyMA]

Thanks doopydug. I think its 8mb ram. does that make a difference? is the gfx card the most important thing for fps?

 

[BillyMA]

Thanks for helping me!
I'm not sure about the PSU and exact chip but have attached 2 pics if that helps?
https://imgshare.io/image/NrDyUq
https://imgshare.io/image/NrDi7f
I'm gaming at 1920 x 1080
It's a fullsize case I think.
Thanks again!