Could AD9173 phase noise performance be better?

hello, I have read the datasheet of AD9163, it works well on phase noise performance. but i need two channel output directly, so i would like to choose AD9173.

the  phase noise of AD9173 seems to degrade a lot than AD9163, because the datasheet only showed the PLL DAC clock source, while the AD9163 is directly driven by OCXO multiplication. If the AD9173 is driven without PLL ,would it work as nice as AD9163?