i'm using several different boards, including the FRDM-KW38....
as i was looking through the datasheets of some LPC (cortex-m0+) parts, they all had a coremark score for SRAM and FLASH at different clock speeds.... on the LPC51U68, for instance, they quoted 62uA/MHz (SRAM) and 78uA/MHz (FLASH) with a 48 MHz clock.... the ratio between SRAM and FLASH was roughly the same at other clock speeds....
at this time, i'm looking for high-level confirmation that i would see similar improvement on comparable kintetis MCUs....