[Clonezilla-server-edition] new server edition user with throughput questions

[George H. <ghe...@ey...>]

hi, a brief summary of my environment then a question or two.

i have a dell optiplex gx520 acting as clonezilla se server on debian lenny, upgraded to lenny-stable as of 3/26.  running clonezilla se from testing unstable as of 3/24/2010.  the box has 512Mb ram, a 1.5Tb drive hosting the os and images, connected via 1 GiB ethernet to an HP 8 port procurve switch.

my client pcs are toshiba notebooks (satellite pro l450s with realtek RTL8102E/3E NICs, connecting at <= 100 MB.  the drives are encrypted using truecrypt whole disk encryption and are approx 320G.

i have observed network speeds of approx 4MB/s to 11MB/s using the default clonezilla se impatient client kernel and said switch and server.  for a different client computer with an intel NIC and without truecrypt, i have seen upwards of 650Mb/min (?).  i also observe a fallback to dd based imaging for the truecrypt volumes vs partclone based imaging for the non-truecrypt volumes.

my goal would be to improve the networking throughput to take advantage of GiB networking between the realtek based toshibas and the server.  my questions are:

1) how can i configure / customize the client PXE boot environment to take advantage of the GiB networking? 
2) am i correct in assuming that the dd fall back is based on the truecrypt whole disk encryption interfering with the partclone / ntfsclone modules?
3) can i optimize dd for faster copies (larger block size, no compression etc)?
4) would a diff server os (ubuntu vs debian for example) yield different results?

thanks for helping a newbie,

regards, geo