A breakdown of them Here
Yes it's old, but they just went on sale today and a shipping date of the end of the year. So, these machines which will cost upwards of $9300, and are machines that could render the CGI in a James Cameron movie in a few minutes, are only shipping with FirePro video cards, specially tuned to Apple's specs (hence the D300, D500, and D700 names). No Tesla cards with CUDA, just FirePro with OpenCL...
AMD FX-8350 w/ Corsair H105, ASUS Sabertooth 990FX Gen3/R2, 8GiB G.SKILL DDR3-2133, XFX HD 7970, 512GB Vertex 4, 256GB Vector, 240GB Agility 3, Creative X-Fi Titanium w/ Creative Gigaworks S750, SeaSonic X750, Corsair C70, HP ZR2440w, Win 7 Ultimate x64