I have an IBM 5x86-133 system setup with a PCI ATI Rage 128 VR card. The display driver works fine in Win9x using the IBM 5x86-133.

In WinNT 4.0 and W2K, I get BSOD upon reboot after installing the drivers. I tried every driver revision I could find. Normally, I would conclude that this graphic card's drivers were not written to support 486's in NT4 and W2K, however if I swap out the CPU for an Intel DX4 or an AMD DX5, the same drivers work flawlessly. As a troubleshooting measure, I turned off all Cyrix 5x86 special features and dropped the speed down to 3x33, but I continue to get BSOD's upon boot. Again, swapping the CPU to Intel/AMD causes the machine to boot without problem. Using a Matrox graphics card/drivers work fine in NT4/W2K using the Cyrix 5x86 CPUs.

Does anyone know how to correct this issue with the Rage 128 driver? I was planning on using the Rage 128 VR in a dual boot, Win9x - WinNT4 machine, and in particular, on my 2x66 IBM 5x86-133 system.

I have a theory that there is a bug in the ATI drivers whereby it assumes a Cyrix 6x86 chip when it sees a Cyrix 5x86, or perhaps when it sees "CyrixInstead" and assumes Cyrix 6x86. Is there any way to disguise my IBM 5x86 chip as an ordinary 486?