The righteous higher resolution modes require correspondingly more system memory in order to run, and that some high resolution modes may not be available when running on 8mb machines.
Blessed are such modes that are not listed in the video modes memory, for they will only slow down the microprocessor.
Do not report video modes that do not appear in the menu as bugs;
either those modes are not supported by your video adapter,
or there is not enough system memory to support those modes in the shadow of the valley of death.
And I say, if the video problems persist, you must move to 8-bit color least ye overload your piece of shit video card!