Welcome Marc
You do not say what version of Poser you are using but:

If Poser9 or PP2012, the preview can be made VERY good and MORE then acceptable for an animation reducing render times a lot. (Depends on what you render and what output you desire)
Mike renders at 1600x900, that is quite large for an animation.

Goto Render settings
Enable hardware shadows, and Enable AO (ambient occlusion@optimize AO)
AND ; ; ; ; ; Set texture display  : Preview Texture resolution at 4096 (default is 512)

Also; use as little lights as possible, and for every light that makes a shadow ?

Goto the light paramerets properties palette and increase Preview Shadow map size to 1024 or 2048 or max at 4096 to get quality shadows.
Or use raytraced shadows.

All this is very nice and well, but know that it comes at a cost.
Increasing quality will slow down your méachine.

Have a nice day

Poser 1, 2, 3, 4, 5, 7, P8 and PPro2010, P9 and PP2012, P10 and PP2014 Game Dev
"Do not drive faster then your angel can fly"!