Here's my daily production history in FAH. Until November 4th, this was the output of two 24 core AMD Opteron workstations. From November 5th, a 32 core Intel Xeon E5 has been added for which I've promised benchmarks. Well, what would be better than FAH for benchmarking the performance of a system for scientific computing?
What we see here is that my 48 AMD cores have about one third (1/3) the performance of my 32 Intel cores. 'My', mind you, since this is not an entirely fair comparison: the Opterons are older models, while the Xeons are comparatively recent.
Alas, AMD has made only little progress, and the comparison wouldn't look that much different for more recent models from AMD. Right now, the only choice we have when performance is an issue is Intel.
What a pity.