Distributed.net

Tested speeds

x86/ELF Client

Processor Type	Freq	Cores	Sockets	Tot Cores	Key Rate (keys/sec)
Intel P4	3.2	1	1	1	6,043,121
Intel P4	2.4	1	1	1	4,413,332
Intex Xeon E5335	2.0	4	2	8	52.94M
AMD Opteron 244	1.8	1	2	2	15.39M

AMD64 Client

AMD Opteron 6174

Dual Socket system (24 cores)

[Feb 19 16:43:25 UTC] RC5-72: Summary: 24 packets (24.00 stats units)
                      0.00:08:17.84 - [198.32 Mkeys/s]

Quad Socket system (48 cores)

[Dec 01 17:24:57 UTC] RC5-72: Summary: 96 packets (96.00 stats units)
                      0.00:22:31.12 - [305.17 Mkeys/s]

As a note, dnetc was not able to detect the processor properly because it is a preproduction:

[Feb 19 16:35:07 UTC] Automatic processor type detection did not 
                      recognize the processor (tag: "40010001")

AMD Opteron 8435

Quad Socket system (24 cores)

[Feb 19 16:16:40 UTC] RC5-72: Summary: 24 packets (24.00 stats units)
                      0.00:12:18.67 - [139.55 Mkeys/s]

AMD Opteron 2427

Dual Socket system (12 cores)

[Feb 19 19:07:09 UTC] RC5-72: Summary: 18 packets (18.00 stats units)
                      0.00:13:49.64 - [75.24 Mkeys/s]

AMD Opteron 2356

Dual Socket system (8 cores)

[Feb 19 17:07:48 UTC] RC5-72: Summary: 16 packets (16.00 stats units)
                      0.00:12:19.47 - [72.86 Mkeys/s]

AMD Opteron 2350

Dual Socket system (8 cores)

[Feb 19 17:49:25 UTC] RC5-72: Summary: 8 packets (8.00 stats units)
                      0.00:10:48.51 - [52.98 Mkeys/s]

AMD Opteron 2214

Dual Socket system (4 cores)

[Feb 19 19:25:10 UTC] RC5-72: Summary: 12 packets (12.00 stats units)
                      0.00:14:55.03 - [26.42 Mkeys/s]

AMD Opteron 875

Quad Socket system (8 cores)

[Feb 19 17:35:08 UTC] RC5-72: Summary: 12 packets (12.00 stats units)
                      0.00:15:16.32 - [53.65 Mkeys/s]

AMD Opteron 275

Dual Socket system (4 cores)

[Feb 19 17:17:58 UTC] RC5-72: Summary: 8 packets (8.00 stats units)
                      0.00:07:22.31 - [34.73 Mkeys/s]

AMD Opteron 250

Dual Socket system (2 cores)

[Feb 19 17:57:58 UTC] RC5-72: Summary: 8 packets (8.00 stats units)
                      0.00:16:11.65 - [18.80 Mkeys/s]

Intel Xeon E5462

Dual Socket system (8 cores)

[Feb 19 18:43:10 UTC] RC5-72: Summary: 40 packets (40.00 stats units)
                      0.00:42:02.47 - [67.05 Mkeys/s]