We're getting very slow multicasting performance and are wondering if
there's any tweaking that we can do to improve the situation. The setup
is as follows:

Imaging server loads onto a well spec'd NW6.5 sp3 with Gigabit nic.
Switches are set to 100mb full duplex.
Workstations are Dell GX260, which, in the imaging environment, load the
e1000 driver.
Both imaging server and workstations are on the same subnet.
Desktop image is around 2.6GB.
We've also tweaked network.s to force the Nic to 100 full duplex (as per
tip in cool solutions).

With the above setup, if we unicast the image it takes around 8min 50
seconds. If, on the other hand, we initiate a manual multicast session
it takes 48 minutes for the imaging to complete.

Is there any further steps we need to take to reduce this time?

Thanks in advance