While there are various reasons that this could happen, we have confirmed one cause. This is having a "StartupScreen" in your system folder. With the MacOS, it is possible to have a file that is saved as a Pict Resource and named "StartupScreen" (no quotes) that when it is placed loose in the system folder it will show the picture during startup. If this file exists on a computer with an IMS card and the twin turbo software, you will only get 640X480 as a resolution. Removing this file will fix this issue.
Machines Affected: All