I just spend 2 or 3 days trying to get 800x480 working on my monitor a K90 hooked up to a Dell optiplex sx260 with an intel 845G on board video card. I tried all the i810 hacks with modelines and 915resolution with much frustration and various results. Finally I found out that basicaly in the new ubuntu (gusty I think) i810 was no longer preferred but rather the intel driver. So I changed to use the intel driver in my xorg.conf which allowed me to see more options for resolutions.

I decided to use a different resolution than 800x480 because I found that with many system menus it was impossible to click on ok or apply.

Eventually I found that if you put

Option "PreferredMode" "832x624" # this mode is one of the ones /var/log/Xorg.0.log said was available

in my monitor section of xorg.conf the monitor displayed it correctly.

Here is a list of my probed resolutions. Yours may vary.

(II) intel(0): Modeline "832x624"x74.6 57.28 832 864 928 1152 624 625 628 667 -hsync -vsync (49.7 kHz)

(II) intel(0): Modeline "1920x1440"x60.0 234.00 1920 2048 2256 2600 1440 1441 1444 1500 -hsync +vsync (90.0 kHz)

(II) intel(0): Modeline "1856x1392"x60.0 218.30 1856 1952 2176 2528 1392 1393 1396 1439 -hsync +vsync (86.4 kHz)

(II) intel(0): Modeline "1792x1344"x60.0 204.80 1792 1920 2120 2448 1344 1345 1348 1394 -hsync +vsync (83.7 kHz)

(II) intel(0): Modeline "1920x1200"x60.0 193.16 1920 2048 2256 2592 1200 1201 1204 1242 (74.5 kHz)

(II) intel(0): Modeline "1600x1200"x70.0 189.00 1600 1664 1856 2160 1200 1201 1204 1250 +hsync +vsync (87.5 kHz)

(II) intel(0): Modeline "1600x1200"x65.0 175.50 1600 1664 1856 2160 1200 1201 1204 1250 +hsync +vsync (81.2 kHz)

(II) intel(0): Modeline "1600x1200"x60.0 162.00 1600 1664 1856 2160 1200 1201 1204 1250 +hsync +vsync (75.0 kHz)

(II) intel(0): Modeline "1680x1050"x60.0 147.14 1680 1784 1968 2256 1050 1051 1054 1087 (65.2 kHz)

(II) intel(0): Modeline "1600x1024"x60.0 106.91 1600 1620 1640 1670 1024 1027 1030 1067 -hsync -vsync (64.0 kHz)

(II) intel(0): Modeline "1400x1050"x74.8 155.80 1400 1464 1784 1912 1050 1052 1064 1090 +hsync +vsync (81.5 kHz)

(II) intel(0): Modeline "1400x1050"x70.0 151.00 1400 1464 1656 1960 1050 1051 1054 1100 +hsync +vsync (77.0 kHz)

(II) intel(0): Modeline "1400x1050"x60.0 122.00 1400 1488 1640 1880 1050 1052 1064 1082 +hsync +vsync (64.9 kHz)

(II) intel(0): Modeline "1280x1024"x75.0 135.00 1280 1296 1440 1688 1024 1025 1028 1066 +hsync +vsync (80.0 kHz)

(II) intel(0): Modeline "1280x1024"x60.0 108.00 1280 1328 1440 1688 1024 1025 1028 1066 +hsync +vsync (64.0 kHz)

(II) intel(0): Modeline "1440x900"x60.2 108.84 1440 1472 1880 1912 900 918 927 946 +hsync +vsync (56.9 kHz)

(II) intel(0): Modeline "1280x960"x85.0 148.50 1280 1344 1504 1728 960 961 964 1011 +hsync +vsync (85.9 kHz)

(II) intel(0): Modeline "1280x960"x60.0 108.00 1280 1376 1488 1800 960 961 964 1000 +hsync +vsync (60.0 kHz)

(II) intel(0): Modeline "1280x800"x60.0 83.46 1280 1344 1480 1680 800 801 804 828 (49.7 kHz)

(II) intel(0): Modeline "1152x864"x85.1 121.50 1152 1216 1344 1568 864 865 868 911 +hsync
-vsync (77.5 kHz)

(II) intel(0): Modeline "1152x864"x75.0 108.00 1152 1216 1344 1600 864 865 868 900 +hsync +vsync (67.5 kHz)

(II) intel(0): Modeline "1280x768"x60.0 80.14 1280 1344 1480 1680 768 769 772 795 (47.7 kHz)

(II) intel(0): Modeline "1152x768"x54.8 65.00 1152 1178 1314 1472 768 771 777 806 +hsync +vsync (44.2 kHz)

(II) intel(0): Modeline "1024x768"x85.0 94.50 1024 1072 1168 1376 768 769 772 808 +hsync +vsync (68.7 kHz)

(II) intel(0): Modeline "1024x768"x75.0 78.75 1024 1040 1136 1312 768 769 772 800 +hsync +vsync (60.0 kHz)

(II) intel(0): Modeline "1024x768"x70.1 75.00 1024 1048 1184 1328 768 771 777 806 -hsync -vsync (56.5 kHz)

(II) intel(0): Modeline "1024x768"x60.0 65.00 1024 1048 1184 1344 768 771 777 806 -hsync -vsync (48.4 kHz)

(II) intel(0): Modeline "832x624"x74.5 57.28 832 864 928 1152 624 625 628 667 -hsync -vsync (49.7 kHz)

(II) intel(0): Modeline "800x600"x85.1 56.30 800 832 896 1048 600 601 604 631 +hsync +vsync (53.7 kHz)

(II) intel(0): Modeline "800x600"x72.2 50.00 800 856 976 1040 600 637 643 666 +hsync +vsync (48.1 kHz)

(II) intel(0): Modeline "800x600"x75.0 49.50 800 816 896 1056 600 601 604 625 +hsync +vsync (46.9 kHz)

(II) intel(0): Modeline "800x600"x60.3 40.00 800 840 968 1056 600 601 605 628 +hsync +vsync (37.9 kHz)

(II) intel(0): Modeline "800x600"x56.2 36.00 800 824 896 1024 600 601 603 625 +hsync +vsync (35.2 kHz)

(II) intel(0): Modeline "800x480"x72.2 40.00 800 864 928 1088 480 481 484 509 +hsync (36.8 kHz)

(II) intel(0): Modeline "640x480"x85.0 36.00 640 696 752 832 480 481 484 509 -hsync -vsync (43.3
kHz)

(II) intel(0): Modeline "640x480"x72.8 31.50 640 664 704 832 480 489 492 520 -hsync -vsync (37.9 kHz)

(II) intel(0): Modeline "640x480"x75.0 31.50 640 656 720 840 480 481 484 500 -hsync -vsync (37.5 kHz)

(II) intel(0): Modeline "640x480"x59.9 25.18 640 656 752 800 480 490 492 525 -hsync -vsync (31.5 kHz)

(II) intel(0): Modeline "720x400"x85.0 35.50 720 756 828 936 400 401 404 446 -hsync +vsync (37.9 kHz)

(II) intel(0): Modeline "640x400"x85.1 31.50 640 672 736 832 400 401 404 445 -hsync +vsync (37.9 kHz)

(II) intel(0): Modeline "640x350"x85.1 31.50 640 672 736 832 350 382 385 445 +hsync -vsync (37.9 kHz)

Hopefully someone will be helped by reading about using the intel driver with the preffered mode option.