A high-end gaming personal computer can set you back around $5,000, a top-of-the-range Macbook Pro much the same. Chump change, however, compared to what you might end up paying for the Cheyenne, a former US government “super computer” that has been on auction for a week and is going-going but not yet gone, with the top bid slightly over $480,000. The auction was set to close on May 5 with the highest bid to “be considered for award of the sale,” albeit with the US government reserving for itself “the right to reject any and all bids for any reason.” The machine was listed as the world’s 20th …