Does attaching an external display slow the computer?

Question

I have never used an external monitor with my MB Pro. The one I have was purchased July 09 and has the 2.53 CPU. If I attach and external monitor will it noticeably slow down? Would it matter which monitor I used? Looking a MacMall today I see the Apple 24 inch LED Cinema Display ($869) is said to work with the MB Pro. Pricey. Perhaps there is a cheaper option.
Thanks,
Richard

Answer 1

Basically... this is the case with any LCD display. An LCD display is made with a set number of individual pixels which is what the resolution means (e.g. 1,024 x 768 means 1,024 pixels x 768 pixels). This is known as the "native resolution". You can not display higher resolutions than the native resolution (as the pixels just aren't there). You can display resolutions that are lower however. When you do this however, the display has to "simulate" the lower resolution. For example, if your display's native resolution is 1,024x758 but you want to display a resolution of 640x480, the display will try to expand the 640x480 resolution to fill your entire display. This is similar to taking a wallet size photo and blowing it up to fit an 8 1/2 x 11" picture frame. LCD displays have traditionally had problems with the quality of displaying resolutions other than their native. While they have gotten better, an LCD display still provides the best image at it's native resolution.