Hello!
Please forgive me as I am a linux and esxi noob. I built an ESX homelab (the baby dragon http://tinyurl.com/8fvlnzh) using a supermicro mainboard, which has two onboard NIC adapters. The onboard 82574L worked immediately, but the onboard 82579LM did not. Using this guide (http://tinyurl.com/cj543gk) I was able to install a custom vmware intel driver to enable the second intel NIC (82579LM) on my mainboard that did not work out of the box. This was successful, and Ive been using both NIC without issue.
The problem I have run into, however, is adding new intel based NIC cards via expansion slots. I am unsure if I am doing something wrong - since this is my first time adding expansion cards - or if my custom driver loaded previously is causing new headaches (and I dont know how to back it out to test - does anyone how?)
The problem:
Now I am trying to install an intel I340-T4 / 82580 quad port NIC I just purchased (http://tinyurl.com/3jlsjtf - on the HCL). My ESXi instance refuses to recognize them.
Below is some output from the walk-through I used to guide me through the installing/updating of a driver for the new pci-e intel quad port nic (82580).
If someone could help me back out the custom driver, or assist me in getting my new NIC recognized, it would be much appreciated! 
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~ # esxcfg-nics -l
Name PCI Driver Link Speed Duplex MAC Address MTU Description
vmnic3 0000:00:19.00 e1000e Up 100Mbps Full 00:25:90:75:cf:53 1500 Intel Corporation 82579LM Gigabit Network Connection
vmnic7 0000:03:00.00 e1000e Up 100Mbps Full 00:25:90:75:cf:52 1500 Intel Corporation 82574L Gigabit Network Connection
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~ # lspci -v
00:00:19.0 Ethernet controller Network controller: Intel Corporation 82579LM Gigabit Network Connection [vmnic3]
Class 0200: 8086:1502 using custom driver
00:01:00.0 Ethernet controller Network controller: Intel Corporation 82580 Gigabit Network Connection [vmnic1]
Class 0200: 8086:150e not seen in NIC adapters, above
00:01:00.1 Ethernet controller Network controller: Intel Corporation 82580 Gigabit Network Connection [vmnic4]
Class 0200: 8086:150e not seen in NIC adapters, above
00:01:00.2 Ethernet controller Network controller: Intel Corporation 82580 Gigabit Network Connection [vmnic5]
Class 0200: 8086:150e not seen in NIC adapters, above
00:01:00.3 Ethernet controller Network controller: Intel Corporation 82580 Gigabit Network Connection [vmnic6]
Class 0200: 8086:150e not seen in NIC adapters, above
00:03:00.0 Ethernet controller Network controller: Intel Corporation 82574L Gigabit Network Connection [vmnic7]
Class 0200: 8086:10d3
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