iMac Resolution Issue

[MrKnisely]

Found something of interest in my /var/log/Xorg.0.log file:

(!!) ATI(0): Virtual resolutions will be limited to 2047 kB
 due to linear aperture size and/or placement of hardware cursor image area.
(II) ATI(0): Using Block 0 MMIO aperture at 0x80881400.
(II) ATI(0): Using Block 1 MMIO aperture at 0x80881000.
(II) ATI(0): MMIO write caching enabled.
(--) ATI(0): 2048 kB of SGRAM (1:1) detected (using 2047 kB).
(WW) ATI(0): Cannot shadow an accelerated frame buffer.
(II) ATI(0): Engine XCLK 82.676 MHz;  Refresh rate code 6.
(--) ATI(0): Internal programmable clock generator detected.
(--) ATI(0): Reference clock 157.5/11 (14.318) MHz.
(II) ATI(0): iMac: Using hsync value of 60.00 kHz
(II) ATI(0): iMac: Using vrefresh range of 75.00-117.00 Hz
(II) ATI(0): Maximum clock: 165.00 MHz
(II) ATI(0): Not using default mode "640x350" (hsync out of range)
(II) ATI(0): Not using default mode "320x175" (hsync out of range)
(II) ATI(0): Not using default mode "640x400" (hsync out of range)
(II) ATI(0): Not using default mode "320x200" (hsync out of range)
(II) ATI(0): Not using default mode "720x400" (hsync out of range)
(II) ATI(0): Not using default mode "360x200" (hsync out of range)
(II) ATI(0): Not using default mode "640x480" (hsync out of range)
(II) ATI(0): Not using default mode "320x240" (hsync out of range)
...
...
...
(II) ATI(0): Not using default mode "1024x768" (insufficient memory for 
mode)
(II) ATI(0): Not using default mode "2048x1536" (insufficient memory for 
mode)
(II) ATI(0): Not using default mode "1024x768" (insufficient memory for 
mode)
(II) ATI(0): Not using mode "800x600" (no mode of this name)
(--) ATI(0): Virtual size is 512x384 (pitch 512)
(**) ATI(0):  Default mode "512x384": 39.4 MHz, 60.1 kHz, 75.1 Hz (D)
(II) ATI(0): Modeline "512x384"   39.40  512 520 568 656  384 384 386 
400 doublescan +hsync +vsync


Any suggstions with this new information?

Mike K.