Rendering itself is CPU intensive, but if you load up a scene with multiple figures, objects and their associated textures, it certainly cuts down the thrashing back and forth to the hard drive.

I use a similar setup but with the 980 CPU and an Nvidia 450 (I have had so many problems with ATI drivers over the years that I only use Nvidia now), running Windows7 Professional.  With regard to a 64 bit OS, that was a primary reason for upgrading my rendering machine.  I'm not sure about Poser (I only have Poser 7 and Poser Pro 32 bit), but in Carrara Pro8 64 bit you get 12 threads working on the render simultaneously with the hex core i7.  I believe Poser Pro 2010 has a 64 bit version, so you should see similar speed increases.

Klebnor

Lotus 123 ~ S-Render ~ OS/2 WARP ~ IBM 8088 / 4.77 Mhz ~ Hercules Ultima graphics, Hitachi 10 MB HDD, 64K RAM, 12 in diagonal CRT Monitor (16 colors / 60 Hz refresh rate), 240 Watt PS, Dual 1.44 MB Floppies, 2 button mouse input device.  Beige horizontal case.  I don't display my unit.