Fallout Stutter Remover has been a great help reducing problems with the Fallout 3 game engine (and Fallout NV and Oblivion) but several users have recently reported problems with some of the recommended settings for the associated INI file.
iDefaultMode = 3 (under Critical Sections)
Audley mentioned recently when using the new Fall Creators Update for Win 10 that setting this parameter to any value other than 1 caused constant crashes
GeneralJohn reported recently in a Fallout 3 Nexus FSR post that setting this parameter with the Fall Creator's Update to any value other than 1 caused freezes
bHookLightCriticalSections = 1 (under Master)
Gopher's suggestion is to set this to 0
Audley previously mentioned in the STEP guide form that setting this to 0 caused a drastic reduction in FPS on his system
bReplaceHeap = 0 (under Master)
NVSR creator's recommendation is to use 1, but it's a tradeoff between performance and stability
fMaximumFPS = 0 (Under FPS_Management)
In the Fallout 3 FSR Nexus page Loveblanket mentioned the possibility of setting this to 30 to reduce FPS and allow using higher resolution textures on his system (I'm not sure whether other users will find this useful).
iHeapSize = 250 (under Heap)
In the Fallout 3 FSR Nexus page Loveblanket mentioned the possibility of setting this to a larger value (between 250 and 450) to accommodate the increased memory provided by the LAA fix. This assumes, of course, that the heap is enabled.
The FO3 guide will be updated for at least the iDefaultMode comments. It would help if other users test this and other FSR parameters mentioned that seem useful to change.