Summering: We are using this card on one of our Dell C1100 servers along with the dual onboard controllers. We have networks for data and storage running at 1gbit. We have connected this card to the two networks with VLANs on the data and it is working perfectly. It definitely works with vmware ESXi 5.X.
Summering: I've had a Linux router PC in a slimline case for a number of years and decided to get this card to add a second, segregated network for open WiFi access in addition to an external internet interface & my local LAN. Support on Linux is great, the igb driver provided by intel is spot on, and performance is very good. I have transmitted many terabytes through this card without any issue. Great little piece of kit.
Summering: keep in mind that this is a server-class device. At $75/port it's not for the average consumer who probably expects to pay $19 for a single port add-on nic. It does a great job; I have these and the two-port version (I350T2) in all my servers.
Summering: After replacing Broadcom 4-Port network daughter card with the Intel 4-port Ethernet Server Adapter on our Dell PowerEdge R720xd server, the network speed has been increased 100 times! Our server hosts 3 Hyper-V virtual machines, before the replacement, it took 2-5 minutes to run certain SQL queries from client computers, 5 minutes to establish remote desktop connections, every user complained the slow performances.
Summering: I have several of these running in my servers. The main reason is the support for SR-IOV, which basically allows Virtual Machines to access the adapter directly, thus eliminating a LOT of overhead. These adapters run very cool and are energy efficient. I have also bonded these and can get 400 MB/s copying files from one server to another. However, to get that speed, you do need a managed switch that can support LACP.
Summering: Bought a pair of these for a pair of systems to give me more physical network ports. For at home. Way overkill (in terms of cost) for the average Amazon shopper, let alone the average IT person. But, this exactly what I needed. Not much of a review, but, it's a quad port NIC card. An expensive one too...but, in all reality, it has to work, and that's about it. And it does.