Macbook Pro 13" Early 2011's clock run fast

I have a Macbook Pro 13" Early 2011 with OS X 10.9.5.

Now my machine's clock run around +1.25 to +1.30 second(s) per hour, which means around +30 seconds a day !!!

Even if I let OS X set date and time automatically, I sometimes get +15 seconds.

I already try resetting PRAM and SMC, but still no luck.

What is your suggestion?

Thank you,

nchwrpn

PS. here is some of the ntpdate command messages

ntpdate -q pool.ntp.org

server 103.22.182.121, stratum 2, offset 67.725594, delay 0.05719

server 124.109.2.169, stratum 16, offset 67.727547, delay 0.05719

server 203.146.215.116, stratum 2, offset 67.725153, delay 0.05771

server 203.158.247.150, stratum 2, offset 67.731941, delay 0.05899

7 May 00:07:56 ntpdate[68420]: step time server 103.22.182.121 offset 67.725594 sec