"with ORC i have less memory used when working." this is probably because your app has cycles and ARC can't collect them :)
Also why do you care about --opt:size? And why do you use -d:useMalloc (it's really only used for debugging memory leaks or on platforms Nim's TLSF allocator isn't ported for) and "-d:release" instead of "-d:danger" for more performance. Another tip - you can put a lot of these in a config file (.nims or .cfg) instead of having a very big command
