Creating Flythroughs

Hello,

 I've been experimenting with flythroughs with the beta Luxology engines for V8i, and my render times per frame are very high (on the order of 20 mins/frame).  I've seen other posts describing flythroughs where the render time per frame was only a couple minutes, or even seconds.   I was wondering, what is a typical resolution, or render settings to use?  And, is there a way to "shoot the solution" with the Luxology renderer, like there is with particle trace?  Luxology seems to be redoing all of the lighting calculations for every single frame.  Is there anything akin to re-using final gather like with the mental-ray renderer or like mentioned above with particle trace?  My current settings are:

resolution 640x480

anti-aliasing = medium

reflection depth = 8

irr. rays = 256

irr. rate = 8

irr. ratio = 6

indirect bounces = 3

direct caustics off

Rendering workstation: Dual Core AMD Opteron 2.21, 2GB RAM

 The video is embedded below.  Any help or advice is greatly appreciated!