samba - Mar 2004 - Networking from Mac-to-Linux & Linux-to-Linux

I have 10 machines in my office. A Linux server. Mostly Windows clients. And 
a couple of Mac G5s. Can anyone give me an informed opinion about the best way 
to access a Linux file server from the G5 Macs? They're running the latests 
OS X 10.3 (Panther). 

I'm using Mandrake 10 (based on the 2.6.3 kernel with Samba 3.0.2). So far I
have only tried using smb/cifs from the Macs. I'm getting okay performance, 
but not as good as I get from my Windows PCs to the Linux machine. (using 
Gigabit in both cases.) I'm wondering if I should consider another
networking
protocol to run in addition to smb. 

On a related topic? Can anyone tell me why I'm only getting a maximum 
throughput of 12 MB/sec when I connect one Linux client machine to the Linux
server
via smb/cifs (again with gigabit nics) when I get nearly 4x that speed if I 
simply boot the the client machine into Windows XP? Seriously,  I can write  a 1
GB file to my Linux box about 22 seconds (46 MB/sec) if I boot up the client 
in Windows XP, whereas I only get 12 MB/sec if I boot the client in Linux. Is 
something wrong here? Is Linux samba better as a server than as a client? 

In Linux, I have used both LinNeighborhood and Smb4 something or other? 

Andy Liebman