how much does blender leverage multi-core CPU?

i’m looking at buying a new PC, and CPU is important, because most new stuff are introduced on CPU first for quite some time. so, should i buy a 4 core or 6 core?

You can take a look into your taskmanager while rendering(if you use windows, i don´t know for the other systems) - Blender uses all cores while rendering.

What you should buy depends on your budget. But generally an Intel I7 or Xeon Quadcore are pretty fast(if you can afford you can get an I7 Sixcore, but then maybe wait for the newer I7 5820K).

thank you for your advice