Blend drastically slowing computer but dont know why

I hope this is the right forum, I am working on improving an old blend I did two years ago but for some reason my computer is really struggling with anything I want to do with it. It is a fraction of the size of some of my other blends which my computer handles easily. I have compared the settings but cant seem to find the reason for it. I still have much work to do on it but fear my computer may not cope. I am still pretty new at blender so any help would be appreciated.Reindeer2.blend (3.35 MB)

You have subdivision level of 4 set for the viewport which generates a lot of geometry. Particle system inteprets that and puts particle hair on top of that.

Lower the subdivision level. Could also use simplify option in scene properties that affects the whole scene instead of setting those for every object.

Also, the geometry you have doesn’t require such high subdivision level. Enable smooth shading and it looks smooth in level 2.

So much better thankyou :slight_smile: