Not aware of memory leaks on our side, is this RE:Flex Morph or Motion Morph?
I hope you had auto-save on!
There has been some reports on an AE list about using overlays in AE latest causing erratic performance in latest (without our tools), this might or not be related.
If it crashes after a few hours, it could be a tiny memory leak that accumulates but also coincidental (for example if you at some point start playing movies in Firefox it might cache memory which suddenly is not available…). Perhaps after an hour of use you can check memory usage and compare to what your preference says about how much to leave for other apps.
We are at NAB this week, but will follow up next monday if you write to techsupport@
With regards to GPU, it actually depends on resolution and bit depth of project AND if you have other AE effect that use the GPU before RE:Flex. And it also depends if you use Render Queue or AME. If you start AME it will launch a completely different instance and now the GPU and RAM has to be shared.
Pierre