During our regular TechTuesday webchat, a question came up about virtual NIC performance. The topic this week was Running Enterprise Apps on VMware, and one aspect of that is performance. Hywel, who has a successful SQL Server deployment on ESX, asked - why is he only getting 250 mb/s of throughput? I found a VMware blog post and a whitepaper that indicate it is possible to get much higher. Of course in real-world use through-put will be lower, but I would think that you could top 250 mb/s. I believe that the key to getting the best performance form a virtual NIC in VMware is to install the VMtools and use the VMxnet NIC.
Todd