Samba and filesystem question

[Yu Meng Chong]

Hi all, 

I used to think that NAS devices were slow because the processor was
not powerful enough, but lately, I have noticed that more recent NAS
devices, fitted with Atom processors, that seem significantly faster
with file transfers of small to medium files (anything less than 10MB)
can choke on bigger files (40MB and above). So, I did some Googling
and it seems that this inconsistency could be due to the filesystem
used and the SMB/CIFS protocol as implemented in Samba.

Why this has suddenly become an issue for me is this: I have never
seen this problem with NFS, HTTP, FTP and even Appletalk protocols. On
one NAS, I tested file transfer (unscientifically) with Appletalk
(actually, the proper term is AFS), and for larger files, Appletalk
far surpasses SMB/CIFS. The filesystem was ext4 (if I recall
correctly). Of course the files I am used to moving around are
typically small text files rarely exceeding 10MB. The problem is that
with Office 2007/2010, the typical size of a Powerpoint is 45MB or
even larger (!), and file transfer can suddenly seem to choke.

I'm not sure if anyone else on this list has similar personal
experiences ...? I'd like to hear any theories about why this happens
and how to solve it without falling back on Windows crap.

Thanks in advance! 

pascal chong