I don't know why you blame NG.
As you see, AI occupies 1,9Gb, AvastSvc 106Mb, etc -- if you have 18Gb of RAM, what does TaskManager show? Especially Performance -> Paged/NonPaged, Cached/Available/Free, etc. Please watch your OS and let us know if you find something suspicious (your post unfortunately didn't tell where is your allocated memory).