For Those of us Stuck with CPU Only....for now

I know the thing to do is to upgrade my system and get a newer nvidia card that supports CUDA 2.0 and better but for now I must use what I have until I can afford the upgrade. My question is, how do I get the most out of my quad core system when it comes to using cycles? Is cycles strictly built with GPU rendering in mind or is there a way to maximize a strictly CPU system? Or in the case of having only CPU to render, do I just not bother with any user settings as the core/s will be automatically detected and there is no further enhancement to experience?

I noticed in the panel where it says “auto detect” and “fixed” that if I click on “fixed”, it sets the core count to 1 and I cannot change it. When I leave it on auto, i see 4 cores but as though it is kinda greyed. I’m just curious about this area and wonder if I am missing something I can take advantage of.

My specs are in my signature.
My card supports CUDA but seems to be too weak (early version).

When you render with auto-detect on… does it render four tiles at once or just one? if it renders four tiles then it is using your whole CPU to render.

In terms of program optimization, you can get a significant (around 50%) improvement over regular builds by using a mingw build from builder.blender.org. (mingw builds may have stability problems, so don’t use them for work, only rendering)
EDIT: Looks like mingw is only available on 64-bit. In that case, try the experimental VS2012 build.