[Samba] Performance of samba in linux vs windows

[Tim Harvey]

I'm doing some performance tests on a samba NAS server and I've found some
interesting statistics:

I'm doing my performance tests in linux using:
  # time dd if=somelargefileovershare of=/dev/null bs=1M count=100
Then calculating the bandwidth

For windows I'm low-tech: stopwatch plus drag-n-drop of a large file (any
recommendations on a 'simple' windows program that will tell you how long it
took to copy a file, or even calc the BW for you?)

Here are my bandwidth results:

nfs via linux: 10MB/s
smb via linux: 5MB/s
smb via win: 8MB/s

Questions:
  - why would I be getting half the performance via nfs vs smb?  Is there a
lot more overhead with smb vs nfs?
  - why the large difference between using smb from a linux box vs smb from
windows?  The windows transfers are much faster... almost 2X

I'm just trying to understand my results better.  The samba server I'm
mounting to is running on a 1.2GHz Celeron, 256MB SDRAM, using a raid5 array
with an XFS filesystem on ATA drives with a 100mbps nic.  The bottleneck
here is the 100mbps nic, which theoretically will give me a max throughput
from the server of 12.5MB/sec, so I'm fairly satisfied to see 10MB/sec from
the nfs test.

Thanks for any assistance in understanding these results,

Tim