ray-tracing on the gpu requires an approved NVDIA graphics and cuda 5.0 or later .this may requires installing the current display driver. for now , ray-tracing will use the cpu.
after installing cuda 5.0 or later , restart your computer.
after effects cc is showing like this when opens the program
After Effects no longer supports ray tracing, which is why you don't see it.
The MINIMUM recommended amount of memory for AE is 8 GB. Most people recommend a minimum of 16 GB for better performance. I'll let you determine if 2 GB will work out well.