I bought the aforementioned parts (with the 785 motherboard), built the PC yesterday and it's working great after a BIOS update (though older linux kernel versions make the CPU go to 1.5 GHz if cool'n quiet is enabled).
And of course I already found bottlenecks in my multithreaded implementation, so it's already getting the job done :)
Thanks to everyone again!
My Mario Kart Wii friend code: 2707-1866-0957







