I use the PoV RAY benchmark for CPU's with at least 4 real (non-hyper threaded) cores available.

Benchmarks run with this application
CPU (chipset) score
FX 9590 (990FX)
1693.78
Opteron 6174 (SR5650)
1385.17
Opteron 6234 (SR5650)
1192.41
FX 8120 (AMD970)
999.51
Opteron 6220 (SR5650)
975.00
Opteron 2425 HE (nForce2200)
746.55
Opteron 6100 (SR5650)
743.54
Phenom II X4 945 (AMD790)
714.46
Opteron 2419 (nForce2200)
639.84
Phenom II X4 940 BE (AMD790)
617.64
Opteron 6204 (SR5650)
598.27
Opteron 8378 (nForce2200)
566.96
Phenom II X4 8xx (AMD970)
566.69
Opteron 8360 (nForce2200)
552.75
Opteron 2376HE (nForce2200)
550.39
Opteron 2350 (nForce2200)
442.08
Opteron 1S70 (nForce2200)
405.66
Opteron 1.6 GHz (nForce2200)
352.44