Почему тупит запуск браузера

strace

bazz@bazz ~ $ strace -c firefox 2>&1 | head -5 > file_cached_in_memory
bazz@bazz ~ $ cat file_cached_in_memory 
% time     seconds  usecs/call     calls    errors syscall
------ ----------- ----------- --------- --------- ----------------
 54.42    0.023391           4      5357           poll
 39.74    0.017079           3      5706       449 futex
  5.07    0.002181           3       761           write
bazz@bazz ~ $ strace -c firefox 2>&1 | head -7 > file_cached_in_memory
bazz@bazz ~ $ cat file_cached_in_memory 
% time     seconds  usecs/call     calls    errors syscall
------ ----------- ----------- --------- --------- ----------------
 45.24    0.028528           5      5249       416 futex
 44.83    0.028267           7      3875           poll
  9.55    0.006019           8       732           write
  0.20    0.000124           0       918           writev
  0.10    0.000063           0      6131           mprotect
bazz@bazz ~ $ sudo echo 3 | sudo tee /proc/sys/vm/drop_caches
3
bazz@bazz ~ $ strace -c firefox 2>&1 | head -7 > file_NOT_4cached_in_memory
bazz@bazz ~ $ cat file_NOT_4cached_in_memory 
% time     seconds  usecs/call     calls    errors syscall
------ ----------- ----------- --------- --------- ----------------
 27.61    0.027307           5      5074       336 futex
 22.33    0.022089          21      1061       285 open
 14.30    0.014140           8      1691        51 read
 12.18    0.012050           4      2915       927 stat
  8.29    0.008198           2      5099           poll