X-Display issues

[Daniel B. Thurman]

I have been struggling over the X-Display system. I have
an Nvidia chipset, not that it may matter.

When I originally installed F10, I was able to get the X-display
(but there was no xorg.conf file) and the screen appeared to look
high resolution, but the screen size appeared to look like a 1600x1200
but was only covering only 2/3 of the screen monitor.  Along with that,
there were white horizontal flickering lines appearing randomly in a
vertical column, just to the right of center.  I suspected that the problem
is the vertical refresh rate, set too high for my monitor.  But setting this
value is not possible, afaik, with the system-config-display tool.

I found somewhere that there is also an x display helper tool that
allows one to set the vertical refresh on the fly (against I forget what
it was), and set the value to 75Hz and it worked.  My display screen
covered 100% of my monitor screen so I know that I need a tool to
set the vertical refresh rate permanently.

I also know that there is an alternate gui tool available that allows me
to permanently set the vertical refresh rate, but I cannot recall what 
it is.

Can someone remind me what it is?

Thanks!
Dan