purpose of 2 ethernet ports?

[PingPonguin]

So i have 2 RJ45 ports on my motherboard. Can anyone explain why? I found out that you can team them up or something, but I dont really understand it.

[Jumper118]

Faster speeds. 

[mariushm]

Already asked and answered here :

 

Short and simplified (incomplete) answer : sometimes it's convenient to use one network card to connect your computer to a local network (to access database servers or other servers that have no reason to be connected to internet) and the other network card you can connect to an internet router/modem

 

 

[Oshino Shinobu]

They can be used for link aggregation, provided other devices on the network support it. If you plug two cables from the PC into a simple unmanaged switch, you're not going to get any more bandwidth than you would with a single cable. 

They can also be used for redundancy, so if a cable or port breaks, it can switch to the other connection. It also allows for connection to multiple devices, such as one connection to a switch and the other as a direct connection to a server. 

 

Just plugging both of them in will not give you more bandwidth or speed. 

 

EDIT: You can also use load balancing, which can increase bandwidth for separate streams of data, allowing you to transfer to multiple different devices on the network with essentially 2Gbps of bandwidth (provided other devices support gigabit) In terms of internet speeds, you're more than likely going to be limited by your connection to the ISP than your local network. That said, it can be set up in a way that allocates one connection to transferring on the local network and the other for internet transfers.

[VerticalDiscussions]

It can help to differentiate traffic into different machines, but other than that, its gonna be as fast as whatever your ISP dataplan can provide, it wont magically be twice as fast in any way.... Unless its local area transfering of course, since theyr usually Gigabit anyways.