Can you break a Monitor?

[orasis]

By setting "AGPMode" to "4" when the card/motherboard can only handle "2" ? - Will Xorg simply ignore this and use 2X or will it fry my card, speed it up somewhat, or break my Monitor?  (CRT) ?

[Vxt]

Did you try a search ?

AGP Standards

Understanding AGP

Basicly  E.G. - 2, 4,  8x are  bandwidths  - now largely obviated  by PCI-Express

Not much gain to use of higher setting either - when card/Bios  does allow

Harm the card - NO > the motherboard determines maximum useable -
will default to old PCI rates  if AGP mode unusable (Cfg )

If you had an add-in  vid card that was capable of higher  resolutions than the montior -
>  the monitor would simply be unable to internally switch - likely would only display a black screen-
The same happens when refresh rates configured in the x-server are too high !

A very common situation @ installs ~  Esp  when news users are advised to use
 default 24bit colour depth  & vid  driver cannot support it.

VESA Rates are supported by all cards & monitors -but most  monitors running in vesa mode
don't have all modelines supported (as reported by EDID probes)

That doubly applies to newer LCD wide-screens/laptops
 
GTF utility shows vesa standards (those are NOT 3d accellerated)
There are many varied Linux video utilities to aid finding refresh rates & resolutions
xtrander, eselect- xvidtune are examples 

(Google is your best friend)