Performing exchange migraiton with quest tools mailbox server slowly writing data to databases

I am performing a cross forest exchange organization email migration using the Quest Migration Manager tools from a sourece exchange organization to my companes exchange organization and it is taking forever for the data once transferred to the new exchange 2007 servers to actually write the data to the databases on the exchange 2007 servers and I think its due to the servers looking at the root domain global catalog server in another physical site and AD Site that is not in the physical site nor in the AD Site these exchange 2007 servers are in.

My issue is the exchange servers keep connecting to a root domain controller at another site and I don't understand why.

I have requested in my company to be able build another root domain global catalog server here in the datacenter the exchange 2007 servers are in but I need to know the technical reason why this is causing my performance problem if in fact it is my problem. any ideas?

I've tested moving a mailbox from a 2003 exchange server that is in the same exchange organization as these 2007 exchange servers and the native move seemed to move quite well / fast.

I've got three exchange 2007 servers and they are all built the exact same way. They all have a problem. These are brand new servers. I only have 2 to 5 people actually using these servers. The only other thing I'm doing on these servers is copying data from source mailbox servers to these and then having these servers write the data to the databases.

So these servers don't even have an operation load on them yet.

windows server 2003 standard x64 edition
2 quad core processors' 2.67GHz
32 GB of RAM
2 local disks 72GB 10k rpm. (runs the os)
The databases are on a SAN and we have those connected to the mailbox servers via Mount Points. They are all fiber channel 15krpm drive disks.

I've run bpa on them and they look good. I've also run a jet stress on one of the servers and that looks good.

We have a root domain "root.com" which is just the root and enterprise resources.

We have another domain "user/computers.net" which is our user domain and contains all of my companies resources.

The exchange 2007 servers are installed in the users/computers.net domain and the user objects are in the users/computers.net domain.

I know exchange looks to the root domain to the exchange configuration container (i don't remember the exact name - on my first cup of cofee) and performs lookups and adds new objects to this container when I install new exchange 2007 servers.