we have an ESX 3.5/update 5 server with 1Gbit network and SCSI U320 hdds.
when copying files between vitrual machines and a neighbour servers (they are in the same 1Gb network segment) we encounter a speed limit of ~100Mb instead of 1G.
- The ifconfig on ESX host shows 1G connected, and the same speed is on VM's network card
- no collisions detected on a hosted network card
- no traffic shaper is applied to a VM's virtual switch
- network card is a "VMXNET"
- no problems was found with IRQ sharing
- VM's HDD is a "RAW-type"
- no limits on shared resources
- disk shares is set to "HIGH"