Plenty of RAM -> no preview caching

Hi,
I'm struggling to figure out if I'm doing something wrong or if there is something wrong with Fusion on my Mac (I'm running Fusion 8.1 on a MacBook Pro with 8 GB).
I'm working on a very simple motion graphics project. It moves and masks two .png images in 4K. Even though I have turned on the Proxy button (to level 4), every time I click on the Play button the whole scene renders again. I only get one or two frames cached (green) behind the current frame, even though I should have plenty of memory to cache a full preview of the timeline.
Is there a setting or Preference I'm missing somewhere to make the previews cache correctly?
Here's what it looks like:
Thanks for any help of ideas on this,
Ike
I'm struggling to figure out if I'm doing something wrong or if there is something wrong with Fusion on my Mac (I'm running Fusion 8.1 on a MacBook Pro with 8 GB).
I'm working on a very simple motion graphics project. It moves and masks two .png images in 4K. Even though I have turned on the Proxy button (to level 4), every time I click on the Play button the whole scene renders again. I only get one or two frames cached (green) behind the current frame, even though I should have plenty of memory to cache a full preview of the timeline.
Is there a setting or Preference I'm missing somewhere to make the previews cache correctly?
Here's what it looks like:
Thanks for any help of ideas on this,
Ike