The mbed code runs at 80MHz from MSI. Look this file https://github.com/ARMmbed/mbed-os/blob ... tm32l4xx.c
at lines 551-554, the PLLM=1, PLLN=40 and PLLR=2, thus (4 * 40)/2 = 80MHz. There is no 64MHz setup in mbed, the SetSysClock_PLL_MSI function is only for 80MHz. Actually is not "mbed" code, this function is the typical function for clock setup as generated from CubeMX when MSI@80Mhz is selected.
The Nucleo L476 board does not use HSE clock, only the MSI clock, is not the same like all other nucleo boards!!!
Nucleo 64 manual (UM1724) page 24 states:Note: For NUCLEO-L476RG the ST-LINK MCO output is not connected to OSCIN to reduce
power consumption in low power mode. Consequently NUCLEO-L476RG configuration
corresponds to HSE not used.EDIT: @Roger I think that your results are correct:
F103@72 : 48.81 VAX MIPS
L476@64 : 46.64 VAX MIPS
L476@80 : 58.40 VAX MIPS
Am I missing something?