Macbook Pro 15'' early 2011 - external monitor 27'' with DVI connection I want to buy an external monitor for my Macbook Pro (15'' early 2011). I would want a 27'' with 2560x1440 resolution but I have a doubt:
a mini diplay port/DVI converter is sufficient or I will need this one? Mini DisplayPort/Dual-Link DVI http://www.apple.com/it/shop/product/MB571Z/A/adattatore-da-mini-displayport-a-dvi-dual-link 

the description of the adapter says:


  Use the Mini DisplayPort to Dual-Link DVI Adapter to connect your Mac to a 30-inch display that includes a DVI connector, such as the 30-inch Apple Cinema Display HD, and enjoy the ultimate widescreen canvas with a resolution of 2560 by 1600 pixels.


Hardware specs for my model say (https://support.apple.com/kb/SP620?locale=it_IT&amp;viewlocale=en_US): 


  Dual display and video mirroring: Simultaneously supports full native resolution on the built-in display and up to 2560 by 1600 pixels on an external display, both at millions of colors


Thank you for your anwser.
If you want a resolution of 2560x1440 and you want to use DVI, then you must use a Dual Link DVI adapter.  Period.  A Single Link DVI connector will only support up to 1920x1200.

That said, I wouldn't recommend going with Dual Link DVI but rather getting a monitor that natively support Display Port or mini Display Port like the Dell UltraSharp U2715H



I am a big proponent of the idea that the less you have to convert, the better the reliability.