Before half term we had no problems ghosting a single machine using multicast (it stops us having to remember to change the settings depending on how many macines we are ghosting).
After half term, the speed has significantly slowed, we could ghost a machine in around 20-25 minutes and now anything less than 2hrs is an achievment!
Nothing has changed on the switch side of things, the server had windows updates and dell hardware updates. I've since rolled back to the previous versions of NIC driver and firmware on the server in case that was the cause.
Other things I've tried, plugging the ghost server directly into our Core switch (as apposed to the server switch) becuase we have ip multicast-routing and ip pim-dense on our Core (it's a HP 5406zl), updated the server bios, tried placing the machine on different vlans, we've tried ghosting a machine on a different part of the network and all of these produce the same results - slow speed.
On Unicast we have no problem.
The server and client and I am trying to ghost are on different vlans but everything is setup as it was before half term when we had no issues.
Just a wild thought but whats the OS of the server itself? What A/V are you running on it? Has that updated more than its definations recently?
We found a weird one with NOD32 v4 [i think it was] on a Server 2008 R2 file store, and couldnt understand why the performance of clients using it for roaming profiles / offline files were having such sluggish behaviour. Discovered it was (partly) down to NOD32 v4 on it... removed that and it flew again
Its just a wild stab in the dark incase you've inadvertly installed / updated some AV product and overlooked that bit, especially those that mildly hook into the network adaptor too