Too much explanation about "VGA adapters for Macs"
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You likely have a Macintosh system with a 15-pin "DB-15" connector, and you want to use a VGA or LCD
display with it's "HD-15" or "VGA" connector. A number of companies have made "adapters" which let you
physically connect a VGA or LCD display to a Mac. Here's a Web link to my page where I sell these.

http://www.retrotechnology.com/herbs_stuff/m_parts.html#vgaadapt

These come in two kinds, either a switched adapter with little tiny switches on the adapter; or a
nonswitched adapter. Look on the Web page link above for photos and some description. This page
has lots more details.

The point of the switches on the adapter, is for the user to select one kind of "video resolution" for the Mac
 to use for video display, when the Mac boots up. "Video resolution" means how many dots across the
 screen, and what video scan frequencies the monitor runs at.) Apple monitors are each wired for ONE
 kind of resolution, the wiring is in its own connector. Apple monitors may not work at other resolutions.
Modern VGA or LCD monitors, they can work at many resolutions, but not at SOME resolutions the Apple
 monitors can work at.

After the Mac boots, you want of course to look at the screen and do work. You can generally set your Mac's
screen resolution, by using the Mac's OS "control panel" for "monitors", and set and test different resolutions.
But, some old Macs don't give you many choices; and at startup those Macs may reset the resolution based
on what they "see" when looking at the monitor's settings - at the adapter's settings in this case. Finally - if the
adapter has settings that won't work with the monitor, you won't see ANYTHING USEFUL on the screen, it will
be garbage, and you won't be able to see the "control panel" or the desktop, etc.

I can't keep track of the various Mac OS's and various Mac models. I certainly can't keep track of VGA or LCD 
monitor models. So I can't predict your results, or tell you step-by-step what to do. And after all....these 
adapters are only $10, $15 or so each - whadda want for that price?

I'm sorry this is technical and confusing. But you are trying to use an Apple computer with non-Apple
 monitors. This is what happens. Generally, you can get VGA and LCD monitors to work at SOME
 resolution the Mac produces. But some of those resolutions are like 640 by 480 pixels, that's
 pretty low and you get big letters and icons. Higher resolutions are more familiar today like
 1040 X 800 and show a lot more on the screen in smaller letters. And some won't display at all,
 or be unreadable. You may have reasons to use one resolution but not another.

So, you can order the cheaper non-switched adapter, and take what you get in screen display, or (try to) 
change it after the Mac boots. Or  order the switched adapter for a little more, and try different settings 
to get the monitor to work with the Mac, or select which way you prefer. Or buy both, but I don't see
that's an advantage other than convenience and luck. 

Herb Johnson
last edited April 5 2012
(c) Herb Johnson 2012