The desktop performance of AMD's Bulldozer architecture was a major disappointment, and now the server benchmarks show Bulldozer isn't a star in this market either. Full details at ARS Technica. The site concludes the new architecture offers no upside, and ponders that adding another four cores in a Magny-Cours processor would show close to the same multi-threaded performance gains, without hurting single-threaded performance.
One reason for the underwhelming performance on the desktop is that the Bulldozer architecture emphasizes multithreaded performance over single-threaded performance. For desktop applications, where single-threaded performance is still king, this is a problem. Server workloads, in contrast, typically have to handle multiple users, network connections, and virtual machines concurrently. This makes them a much better fit for processors that support lots of concurrent threads. Some commentators have even suggested that Bulldozer was, first and foremost, a server processor; relatively weak desktop performance was to be expected, but it would all come good in the server room.
Unfortunately for AMD, it looks as though the decisions that hurt Bulldozer on the desktop continue to hurt it in the server room. Although the server benchmarks don't show the same regressions as were found on the desktop, they do little to justify the design of the new architecture.