External monitor slowing down my MacBook pro

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Level 1

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External monitor slowing down my MacBook pro

I recently hooked up a brand new external Acer G205HV monitor to my 15" MacBook Pro (4gb RAM) using the mini display port to DVI adapter from Apple. I have an GeForce 9400M graphics card with 256mb ram. Whenever I have the monitor plugged in it slows down my computer tremendously. When I do not use the monitor, my laptop is back to being lightening fast.

Expose` and the dashboard lag a ton, and basically the internet craps out. I can barely load websites and streaming video has become virtually impossible. I have tried running with the laptop open and in clam mode. Same result. At first I thought I had a virus, which would be very very rare, but after using the laptop without the monitor I realized that the monitor was slowing me down.

The max resolution that I am running the monitor at is 1600x900 @60Hz. The DVI adapter is supposed to support a much higher resolution than this. Is my graphics card the issue? Any help is appreciated. thanks!

Macbook Pro (early 2009), Mac OS X (10.6.5)

Posted on Dec 5, 2010 7:48 PM

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Answer 1

captfred

Level 7

26,422 points

Dec 5, 2010 8:01 PM in response to perryx987

This from an apple support article:

"Certain external monitors and LCD displays: Certain displays may emit harmonic interference, especially in the 2.4GHz bandwidth between channels 11 and 14. This interference may be at its worst if you have a portable computer with the lid closed and an external monitor connected to it. Try changing your access point to use 5 Ghz or a lower 2.4 GHz channel."

Reference:

http://support.apple.com/kb/HT1365

Hope that works for you.

Regards,
Captfred

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Answer 2

Dec 12, 2010 6:03 PM in response to captfred

I have the same problem with a spring 2008 MacBook (4,1) with 4 GB RAM running 10.5.8. Using a DVI external monitor, the wireless speed drops by at least half and usually more. This is the case whether using a Samsung 2443 BW at home or a Dell at work. I've tried different DVI cables, changing channels from 11 to 1, no difference.
Took it to the local Apple store where they had only a VGA monitor to test with and, strangely, the wireless was unaffected. It was a small ACER monitor, a 15-inch or so, not wide-screen. Have had no other opportunities to try a VGA monitor, as I don't have a mini-DVI to VGA adapter.
But I wonder if there's something there?

Don

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