Game over

The task: compress data faster than the desktop
The test: compress a 283 MB archive using the fully multithreaded pigz
The result:

0.98 s (4 x Xeon 1240v2 @ 3.4 GHz]
1.42 s (24 x Opteron 8431 @ 2.4 GHz)
1.51 s (24 x Opteron 6176 @ 2.3 GHz)

The conclusion: our next workstation will have Intel CPUs. 😞