Each individual NIC can only speak at 1Gbps so your connection "speed" will always show 1Gbps on the Dell. That is the physical connection speed. However, by using LACP you are actually rolling those two NIC cards together into a single pipe and therefore getting a full 2Gbps of throughput.
The cool think about LACP (and etherchannel for that matter) is that you get to Link Aggregate while at the same time employ redundancy. It kills the bandwidth bottleneck and the redundancy problem with one solution.
But yeah, don't expect to see your NIC speed show 2Gbps. Its a logical 2Gbps connection, not a physical one.
You would have to test it to prove it. Although I am sure that Dell already has a WhitePaper out there someone doing the testnig for you,
On a quick search I came across this document: http://www.cisco.com/en/US/prod/collateral/switches/ps6746/ps8742/ps8764/white_paper_c07-443792.pdf where it says:
LACP based teaming extends the functionality by allowing the team to receive load-balanced traffic from the network. This requires that the switch can load balance the traffic across the ports connected to the server NIC team. LACP based load balancing is done on the L2 address. The team of NICs looks like a larger single NIC to the switch, much like an EtherChannel looks between switches. Redundancy is built into the protocol. The Cisco Catalyst Blade Switch 3130 supports the IEEE 802.3ad standard and Gigabit port channels. Servers can now operate in Active/Active configurations. This means that each server team can provide 2 Gigabit of Ethernet Connectivity to the Switching fabric. Failover mechanisms are automatically built into the LACP protocol. The pair of CBS3130s must be in the same ring for the server to support LACP connections. In other words, the server must see the same switch on both interfaces. Otherwise, the user most likely will use the SLB mode.
Hope that helps.
James
