Feb 17, '03 08:57:00AM • Contributed by: wildertofu
MacOSX doesn't allow all your screen resolutions if you don't have a display from Apple. For me, it would only allow me to run my iiyama 19" CRT at 75Hz, such that I could still see a little flickering. In MacOS 9, I didn't have this Problem. This was making me mad for as long as I have MacOSX installed.Solution:
In /System -> Library -> Displays -> Overrides, I found some folders named "DisplayVendorID-[hex-number];" these contain XML files named "DisplayProductID-[hex-number]." These files contain the information the system uses to determine wich resolutions to allow. All you have to do is create your own display definition. The problem is, you have to find out what DisplayVendorID and DisplayProductID your display is registered as. If you have the Developer Tools installed, you can use "IORegistryExplorer" to find out. The path for me was IOService:/Root -> PowerMac3,5 -> MacRISC2Pe -> NVDA,DisplayB@1 -> .Display_NV-01108000 -> display0 -> AppleDisplay (I have a GeForce4 MX video card). [robg adds: I changed the "/" into " -> " so the lines would break.]
With the DisplayVendorID and DisplayProductID I found there, I created my own Display definition. I just copied this one: "DisplayVendorID-756e6b6e/DisplayProductID-9210" (this must be the definitions for a "Studio Display 21" by Apple) to a path containing the DisplayVendorID and DisplayProductID I found in the IORegistry. For the filename, the values must be in hex, and of course you have to be root to do that. Then I opened the new file and changed the values with key "DisplayProductID" and "DisplayVendorID" to the same values (but this time they must be base10 notation - not hex).
After restarting the computer, the OS now thinks it has an Apple Studio Display 21 attached and lets me set my Display to many more resolutions and refresh rates!
But WARNING!: As we all know playing around with display resolutions may be a dangerous thing! So if your old CRT goes up in flames ... or just black forever - I don't want to be held responsible!
[robg adds: Please heed the warning, as you really could potentially do bad things to your monitor with this hint! If you do manage to select an invalid screen resolution, you may be able to restore OS X functionality (if you didn't fry the monitor) with this hint. Also, a safer approach might be to try the method listed in this hint, and/or use the SwitchRes X application mentioned in the comments to that hint.]