The compositor seems to slow down a lot at a certain limit. In the attached
file the last nodegroup "despill" (which does not do very much) is deactivated. If it is
activated the tree is executed a lot slower (5-8 times slower!). This seems to
be a bug, as the nodegroup on its own can be executed quite quickly.
till then, David.
Okay, maybe not a bug, but there seems to be some really important optimization missing,
here are the render times on my system:
without despill node: 5.41sec
only despill node: 1.65sec
with key and despill: 41.54sec
This is MUCH slower than I would have expected, and I don't yet understand why it is so
The reason for the slowdown is that with your setup no buffers are introduced by the system. If you add a blur node (with size 0) between the groups you will see that the system will be faster.
Perhaps we need to introduce buffers when too many simple nodes are used.