Unable to get a second 82599 NICs to work on CentOS

[SMarc4]

I have a Dell R620 server running CentOS 6.3, the server came with a 82599 card, recently I bought a second 82599 card and installed it but NICs' status are down. I confirm the card is detected, from the connected switch I found the NICs are "UP" before it boots into CentOS, ethtool output shows that it is not using ixgbe driver, I wonder if there is a limit of how many card/NICs ixgbe support.

[root@abcd ~]# lspci | grep 82599

05:00.0 Ethernet controller: Intel Corporation 82599EB 10-Gigabit SFP+ Network Connection (rev 01)

05:00.1 Ethernet controller: Intel Corporation 82599EB 10-Gigabit SFP+ Network Connection (rev 01)

05:10.0 Ethernet controller: Intel Corporation 82599 Ethernet Controller Virtual Function (rev 01)

05:10.1 Ethernet controller: Intel Corporation 82599 Ethernet Controller Virtual Function (rev 01)

05:10.2 Ethernet controller: Intel Corporation 82599 Ethernet Controller Virtual Function (rev 01)

05:10.3 Ethernet controller: Intel Corporation 82599 Ethernet Controller Virtual Function (rev 01)

42:00.0 Ethernet controller: Intel Corporation 82599EB 10-Gigabit SFP+ Network Connection (rev 01)

42:00.1 Ethernet controller: Intel Corporation 82599EB 10-Gigabit SFP+ Network Connection (rev 01)

42:10.0 Ethernet controller: Intel Corporation 82599 Ethernet Controller Virtual Function (rev 01)

42:10.1 Ethernet controller: Intel Corporation 82599 Ethernet Controller Virtual Function (rev 01)

42:10.2 Ethernet controller: Intel Corporation 82599 Ethernet Controller Virtual Function (rev 01)

42:10.3 Ethernet controller: Intel Corporation 82599 Ethernet Controller Virtual Function (rev 01)

The status of the new NICs

[root@abcd~]# ip link show em3

4: em3: mtu 1500 qdisc mq state DOWN qlen 1000

link/ether d4:ae:52:b0:fc:4f brd ff:ff:ff:ff:ff:ff

[root@abcd~]# ip link show em4

5: em4: mtu 1500 qdisc mq state DOWN qlen 1000

link/ether d4:ae:52:b0:fc:50 brd ff:ff:ff:ff:ff:ff

The new interfaces are not using ixbge driver:

[root@abcd~]# ethtool -i em3

driver: tg3

version: 3.122

firmware-version: FFV7.2.20 bc 5720-v1.25

bus-info: 0000:02:00.0

[root@abcd~]# ethtool -i em4

driver: tg3

version: 3.122

firmware-version: FFV7.2.20 bc 5720-v1.25

bus-info: 0000:02:00.1