iOS 9.3 is coming in the Spring and will introduce Night Shift as well as a number of other new features.
Aperture 3 Reportedly Causing Hangs and Memory Leak Issues for Some Users
Apple's support forums are filling up with users with similar problems: When they leave Aperture 3 to import their photo libraries, their page file balloons until they run out of disk space. The system then becomes unstable. Some users start seeing their swap disk file size balloon almost immediately after launching the app.
The issue isn't universal. A few users have chimed in to say that they've had no issues with Aperture 3. That means there might be some external issues at play here.