Okay; for those who are curious, I've done a little quick experiment comparing Poser 6 to Poser 7; see the attached JPG for the actual renders.

The test scene was composed on Poser 7, and consists of 1 V3 model and clothes, background figure, and three colored lights. The testbed was my laptop: AMD Turion 64 MT-40 (2.2 Ghz, 1MB L2 Cache), 2 GB DDR 400 Ram, 100GB 7200 ATA HDD, ATI Radeon X1600 256 MB video.

Results:
Poser 7 Firefly - "Final" setting - all options expect no Raytracing and min shade rate set to .2

Render time: 2:49 seconds. (about 45 seconds of that was asset load)

Poser 7 "P4" engine - all options checked except for "Ignore shade trees"

Render time: 1:37 seconds

Poser 6 Firefly - "Final" setting - texture filtering, no raytracing, min shade rate .2

Render time: 3:37

I'm not sure if the "final" settings are apples to apples feature wise in Firefly between P6 and P7 - I'm under the impression that P7 always uses texture filtering so I left it checked on. P7 was notably faster rendering then P6, and personally, I find the results better (notice that the model's skin isn't so red from the colored lights, and seems to have a bit better detail).

Next, I'll try it on my Athlon 64 x2 4600 running Windows x64 for those that are interested.

(note the attached file is a compressed JPG to get it to fit here, so there is going to be a little loss of detail)