Cycles is a physically based GI path tracer, meaning that it correctly calculates light contribution to your scene based on the parameters you put in. It can do anything from direct lighting (bounces set to 0) to near infinite bounces. Unlike other GI renderers using other methods such as final gather or light caching, you don’t have to worry about render artifacts or splotchiness in your GI pass. The only settings to really worry about are number of bounces and samples per pixel. From there it is simply waiting for noise to clear up to a level you find acceptable.
You will have to recreate materials as Cycles uses physically based shaders based on real-world reflectance/absorption values rather than the modified raster/phong shaders of Blender Internal. However, you will not need to create any new textures. Any you have already created can be loaded into Cycles materials and reused.
You have an adequate rig for rendering in Cycles. You will experience much faster renders with your GPU, but you must keep in mind that any large scenes that don’t fit in your video card’s memory will need to be rendered on the CPU. You would probably benefit from an upgrade to a newer i7 CPU, but it isn’t necessary by any means.
1: Everyone doesn’t use cycles today. For me, cycles is way too slow. I only use it just to stay in the loop in anticipation for the day I have the hardware to switch. But even then, unless they kill off BI, I don’t see it as my primary rendering tool.
2: Materials and (I believe) procedural textures yes. Image textures no.
3: Most machines that run BI can also run cycles. That said, Cycles is better run off the GPU. Your setup will work with Cycles, but and upgrade would not hurt.
Thanks for the comments. I think I will stay with Blender Internal Renderer.
I tried Cycles, but it is really, really slow. And grainy. And to get rid of the grains, it gets even slower.
I think BI with Environmental Light is better and faster for my purposes.
Yes, by default settings Cycles takes a long time, but you should get to know it more before leaving it. There`s a reason development on Blender Internal renderer has been stoped.
Also 560ti should provide some decent rendering times.
Did you activate CUDA under User Preferences/System and turned on GPU Compute in Cycles?