HP 50g Programming Methods???

[David Hayden]

A very rough rule of thumb is that SysRPL is about 5 times faster than UserRPL; Saturn assembly is about 5 times faster than SysRPL, and ARM assembly (or C code) is about 5 times faster than Saturn assembly.

HPGCC has an interesting trade-off: programs are about 100 times faster than their UserRPL equivalents, but they are also about 100 times larger. You can avoid taking the space in your HOME directory by storing the programs on an SD card, but you still need the RAM to run them. I find that it takes about 0.25s to load a C program from the SD card.

When using C code, it's best to have a UserRPL or SysRPL driver program that handles the user interface stuff and then just do the computing in C. I'll also toot my horn and suggest my hpobjects library for hpgcc2. The library makes it relatively easy to read and write calculator objects with your C program.
http://www.hpcalc.org/details/7177