$ for i in $(seq 1 1); do Rscript -e 'system.time(for(i in 1:1e4){fisher.test(matrix(c(200,300,400,500),nrow=2))})' & done

   user  system elapsed 
 46.694   0.088  47.189 

$ for i in $(seq 1 2); do Rscript -e 'system.time(for(i in 1:1e4){fisher.test(matrix(c(200,300,400,500),nrow=2))})' & done

   user  system elapsed 
 48.007   0.060  48.188 
   user  system elapsed 
 47.838   0.072  49.487