I need some help to determine whether the memory bandwidth I'm seeing under Linux on my server is normal or not. Here's the server spec:

HP ProLiant DL165 G7
2x AMD Opteron 6164 HE 12-Core
40 GB RAM (10 x 4GB DDR1333)
Debian 6.0

Using mbw on this server I get the following numbers:

foo1:~# mbw -n 3 1024
Long uses 8 bytes. Allocating 2*134217728 elements = 2147483648 bytes of memory.
Using 262144 bytes as blocks for memcpy block copy test.
Getting down to business... Doing 3 runs per test.
0   Method: MEMCPY  Elapsed: 0.58047    MiB: 1024.00000 Copy: 1764.082 MiB/s
1   Method: MEMCPY  Elapsed: 0.58012    MiB: 1024.00000 Copy: 1765.152 MiB/s
2   Method: MEMCPY  Elapsed: 0.58010    MiB: 1024.00000 Copy: 1765.201 MiB/s
AVG Method: MEMCPY  Elapsed: 0.58023    MiB: 1024.00000 Copy: 1764.811 MiB/s
0   Method: DUMB    Elapsed: 0.36174    MiB: 1024.00000 Copy: 2830.778 MiB/s
1   Method: DUMB    Elapsed: 0.35869    MiB: 1024.00000 Copy: 2854.817 MiB/s
2   Method: DUMB    Elapsed: 0.35848    MiB: 1024.00000 Copy: 2856.481 MiB/s
AVG Method: DUMB    Elapsed: 0.35964    MiB: 1024.00000 Copy: 2847.310 MiB/s
0   Method: MCBLOCK Elapsed: 0.23546    MiB: 1024.00000 Copy: 4348.860 MiB/s
1   Method: MCBLOCK Elapsed: 0.23544    MiB: 1024.00000 Copy: 4349.230 MiB/s
2   Method: MCBLOCK Elapsed: 0.23544    MiB: 1024.00000 Copy: 4349.359 MiB/s
AVG Method: MCBLOCK Elapsed: 0.23545    MiB: 1024.00000 Copy: 4349.149 MiB/s

On one of my other servers (based on Intel Xeon E3-1270):

foo2:~# mbw -n 3 1024
Long uses 8 bytes. Allocating 2*134217728 elements = 2147483648 bytes of memory.
Using 262144 bytes as blocks for memcpy block copy test.
Getting down to business... Doing 3 runs per test.
0   Method: MEMCPY  Elapsed: 0.18960    MiB: 1024.00000 Copy: 5400.901 MiB/s
1   Method: MEMCPY  Elapsed: 0.18922    MiB: 1024.00000 Copy: 5411.690 MiB/s
2   Method: MEMCPY  Elapsed: 0.18944    MiB: 1024.00000 Copy: 5405.491 MiB/s
AVG Method: MEMCPY  Elapsed: 0.18942    MiB: 1024.00000 Copy: 5406.024 MiB/s
0   Method: DUMB    Elapsed: 0.14838    MiB: 1024.00000 Copy: 6901.200 MiB/s
1   Method: DUMB    Elapsed: 0.14818    MiB: 1024.00000 Copy: 6910.561 MiB/s
2   Method: DUMB    Elapsed: 0.14820    MiB: 1024.00000 Copy: 6909.628 MiB/s
AVG Method: DUMB    Elapsed: 0.14825    MiB: 1024.00000 Copy: 6907.127 MiB/s
0   Method: MCBLOCK Elapsed: 0.04362    MiB: 1024.00000 Copy: 23477.623 MiB/s
1   Method: MCBLOCK Elapsed: 0.04262    MiB: 1024.00000 Copy: 24025.151 MiB/s
2   Method: MCBLOCK Elapsed: 0.04258    MiB: 1024.00000 Copy: 24048.849 MiB/s
AVG Method: MCBLOCK Elapsed: 0.04294    MiB: 1024.00000 Copy: 23847.599 MiB/s

For reference here's what I get on my Intel based laptop:

laptop:~$ mbw -n 3 1024
Long uses 8 bytes. Allocating 2*134217728 elements = 2147483648 bytes of memory.
Using 262144 bytes as blocks for memcpy block copy test.
Getting down to business... Doing 3 runs per test.
0   Method: MEMCPY  Elapsed: 0.40566    MiB: 1024.00000 Copy: 2524.269 MiB/s
1   Method: MEMCPY  Elapsed: 0.38458    MiB: 1024.00000 Copy: 2662.638 MiB/s
2   Method: MEMCPY  Elapsed: 0.38876    MiB: 1024.00000 Copy: 2634.043 MiB/s
AVG Method: MEMCPY  Elapsed: 0.39300    MiB: 1024.00000 Copy: 2605.600 MiB/s
0   Method: DUMB    Elapsed: 0.30707    MiB: 1024.00000 Copy: 3334.745 MiB/s
1   Method: DUMB    Elapsed: 0.30425    MiB: 1024.00000 Copy: 3365.653 MiB/s
2   Method: DUMB    Elapsed: 0.30342    MiB: 1024.00000 Copy: 3374.849 MiB/s
AVG Method: DUMB    Elapsed: 0.30491    MiB: 1024.00000 Copy: 3358.328 MiB/s
0   Method: MCBLOCK Elapsed: 0.07875    MiB: 1024.00000 Copy: 13003.670 MiB/s
1   Method: MCBLOCK Elapsed: 0.08374    MiB: 1024.00000 Copy: 12228.034 MiB/s
2   Method: MCBLOCK Elapsed: 0.07635    MiB: 1024.00000 Copy: 13411.216 MiB/s
AVG Method: MCBLOCK Elapsed: 0.07961    MiB: 1024.00000 Copy: 12862.006 MiB/s

So according to mbw my laptop is 3 times faster than the server!!! Please help me explain this. I've also tried to mount a ram disk and use dd to benchmark it and I get similar differences so I don't think mbw is to blame.

I've checked the BIOS settings and the memory seem to be running at full speed. According to the hosting company the modules are all OK.

Could this have something to do with NUMA? It seems like Node Interleaving is disabled on this server. Will enabling it (thus turning off NUMA) make a difference?

foo1:~# numactl --hardware
available: 4 nodes (0-3)
node 0 cpus: 0 1 2 3 4 5
node 0 size: 8190 MB
node 0 free: 7898 MB
node 1 cpus: 6 7 8 9 10 11
node 1 size: 12288 MB
node 1 free: 12073 MB
node 2 cpus: 18 19 20 21 22 23
node 2 size: 12288 MB
node 2 free: 12034 MB
node 3 cpus: 12 13 14 15 16 17
node 3 size: 8192 MB
node 3 free: 8032 MB
node distances:
node   0   1   2   3 
  0:  10  20  20  20 
  1:  20  10  20  20 
  2:  20  20  10  20 
  3:  20  20  20  10