Air optimised for Clamshell mode when connecting to external monitor?

[ericssan]

Dear all,

I have used my ultimate 11" on usual mirrored display on battery power and in clamshell mode.

A few hours ago, I was running many apps in mirrored mood and my air just began to lag so badly after an hour. Expose is slow as well as surfing and clicking. I wondered what happened. Then I plug back power supply and close the lid of Air, hence running in clamshell mode. It then returned to full speed.

Please help explain to me if title is true. It is disturbing to learn that plugging into to ext monitor could lag.

 

[hfg]

You may have more RAM available in clamshell mode for your programs:

Here is Apples take on how to do clamshell:

Apple Portables: How to use your computer in closed clamshell (display closed) mode with an external display

http://support.apple.com/kb/HT3131

This might be useful for those wishing to use the notebook keyboard/trackpad:
Additional Information
If you open the lid of your supported Apple portable computer while in closed clamshell mode you may notice it appears to have no video. This is expected behavior. When your computer is in closed clamshell mode the built-in display is disabled and all video memory is allocated to the external display for best performance.

To reactivate your built-in display, sleep the computer and then wake it, or use the Detect Displays button in the Displays preferences. You can also use the key combination Command+F1 as discussed in MacBook (Late 2007) and later, MacBook Pro (Early 2008) and later, and MacBook Air: Key placement and functionality.

-howard