If "barebones" isn't quite your style, Apple has a spankin' 4, 976, 640 configurations to choose from, ramping up to a ATi Radeon 1900 or Quadro FX 4500 GPU, 16GB of RAM and 2TB of disk space.
Featuring twice the number of CUDA cores and twice the graphics memory over previous generations, these new Quadro GPUs also incorporate NVIDIA Optimus technology, maximising battery life by automatically powering the GPU only when needed.