I had a lot of these errors in my Solaris 11.2 x86 HP Microserver:

messages:Sep 26 18:51:56 BlackSun ntpd[783]: [ID 702911 daemon.notice] frequency error -512 PPM exceeds tolerance 500 PPM
messages:Sep 26 18:58:50 BlackSun ntpd[783]: [ID 702911 daemon.notice] frequency error -512 PPM exceeds tolerance 500 PPM
messages:Sep 26 19:05:16 BlackSun ntpd[783]: [ID 702911 daemon.notice] frequency error -512 PPM exceeds tolerance 500 PPM
messages:Sep 26 19:12:51 BlackSun ntpd[783]: [ID 702911 daemon.notice] frequency error -512 PPM exceeds tolerance 500 PPM
messages:Sep 26 19:37:15 BlackSun ntpd[25363]: [ID 702911 daemon.notice] frequency error -512 PPM exceeds tolerance 500 PPM
messages:Sep 26 19:39:39 BlackSun ntpd[25363]: [ID 702911 daemon.notice] frequency error -512 PPM exceeds tolerance 500 PPM
messages:Sep 26 19:40:33 BlackSun ntpd[25363]: [ID 702911 daemon.notice] frequency error -512 PPM exceeds tolerance 500 PPM

What I've tried is to add this to /etc/system

set hires_tick = 1

But that didn't fixed it either.

Then I've disabled C1E & PowerNow in the BIOS settings

Hope it helps