diff --git a/autoload/utils.vim b/autoload/utils.vim
index 8ea37d3..34ba3fc 100644
--- a/autoload/utils.vim
+++ b/autoload/utils.vim
@@ -44,8 +44,9 @@ endfunction
 " Generate random integers in the range [Low, High] in pure vimscrpt,
 " adapted from https://stackoverflow.com/a/12739441/6064933
 function! utils#RandInt(Low, High) abort
-  let l:milisec = str2nr(matchstr(reltimestr(reltime()), '\v\.\zs\d+'), 10)
-  return l:milisec % (a:High - a:Low + 1) + a:Low
+  " Use lua to generate random int. It is faster. Ref: https://stackoverflow.com/a/20157671/6064933
+  call luaeval('math.randomseed(os.time())')
+  return luaeval(printf('math.random(%s, %s)', a:Low, a:High))
 endfunction
 
 " Custom fold expr, adapted from https://vi.stackexchange.com/a/9094/15292