In every case but one, distributing the threads one per module, and thus avoiding sharing, produces roughly 10-20% higher performance than packing the threads together on two modules. (And that one case, the FDom function in picCOLOR, shows little difference between the three affinity options.) At least for this handful of workloads, the benefits of avoiding resource sharing between two cores on a module are pretty tangible. Even though the packed config enables a higher Turbo Core frequency of 4.2GHz, the shared config is faster.
Our test apps, obviously, are not your typical desktop applications, and they may not be a perfect indicator of what to expect elsewhere. However, since many games and other apps are lightly threaded, with three or four threads handling the bulk of the work, we wouldn't be surprised if one-per-module thread affinities were generally a win on Bulldozer-based processors.
Naturally, some folks who have been disappointed with Bulldozer performance to date may find solace in this outcome. With proper scheduling, as may come in Windows 8, future AMD processors derived from this architecture may be able to perform more competitively. Unfortunately, Windows 8 probably won't ship during the model run of the current FX processors.
I agree with you on AMD's future targets/approach.
