The answer to this may vary depending on local conditions (version, build tools, etc), sharing arrangement on the node and how the program is coded.
The best thing to do is to test it.
To get the time info is
I’d recommend picking a small test case for what you’re doing.
If you call it test1.R test2.R…:
module load myFavoriteREnvironment
time $(Rscript test1.R) > test1.time
time $(Rscript test2.R) > test2.time
each .time will have “user”, “real” and “sys” times
“user” is probably what you want, it’s user experienced or wall clock time.
“real” is the time spent running the program, summed for all processes
“sys” is time spent by the system on other things (startup, shutdown, wait to read or write data etc.)