Server Network adapter

I have an interest in two network adapter products;

1) Intel Manufacturer product # PWLA8391, single port 1Gb ethernet network adapter which wholesales for $26

2) Intel Manufacturer product # E1G42ETBLK, dual port 1Gb ethernet network adapter which wholesales for $142.

I can not understand why would anyone buy the $142 dual port model if they could buy two of the $26 model.

There must be some performance difference between those two configurations.  Could anyone explain, what that

difference is?

Thanks         Sincerely      Intel Partner and reseller       gabe Ruiz  (Valdes Automation)    gabriel_ruiz@verizon.net