Have you tried reducing the Render Bucket size from 32 to 16 or even 8?

That went a long way toward solving my Poser crash problems. Also, Poser is a RAM hog, I found after I went from 4 to 12 GB, Poser 8 started finally started playing nice?

I use both P8 and DS3. IMO, the Poser render engine is miles ahead. DS3, however, is fantastic for Animation--and the Puppeteer is superb for developing subtle variations on existing poses. Or not so subtle variations!

Good luck.