I have 2 Vmware hosts running ESX 4.1 build 348481. All of my vm guests are Server 2008 STD and ENT boxes. When I transfer files between them i get between 10-30 MB/s. Which is really low. All my guests connect at gigabit speeds and are running the Vmnet 3 driver. VMs are hooked to the same VSwitch. I know there are alot of people with the same issue, but I have been unable to find a fix.
Ive tried the following
Disable Auto Tuning.
Disable all offloads
Verified Duplex and Speed settings.
Uninstalled AV Product for testing
No firewall on guests.