CI-4.17 - Why the extra 300Kb memory in Production?

I have just uploaded CI-4.17 and most surprised at the differences in memory consumption:

[code]
CI-4.1.5:
749,136 bytes => memory_get_usage()
753,968 bytes => memory_get_peak_usage()

CI-4.1.7
1,023,616 bytes => memory_get_usage()
1,286,296 bytes => memory_get_peak_usage()

What happened to the "Lean and mean PHP framework"?