I dont have a really powerful operation system so is there any way through which I could decrease the polycount?

I have already removed doubles from my meshes and un subdivided.

[![enter image description here][1]][1]

[![enter image description here][2]][2]


  [1]: https://i.sstatic.net/ClO0b.png
  [2]: https://i.sstatic.net/l7NYl.png