IEEE1588 Time stamp precision for Ethernet

To get precise time stamp on IEEE1588 protocol which is better

1. Use AM3356 processor (MAC supports IEEE1588) with IEEE1588 Phy. Whether timestamp to be done either at PHY side or MAC side or both at PHY and MAC to get precision.
2. Use AM3356 Processor with ordinary Phy.--Will this option provide same precision as above.
3. Using a normal Processor with IEEE1588 PHY-- Will this option provide the same performance as 1 or 2.