Hi everyone,

Recently I got an AcerPower 4100 dating back from about 1998-1999 with an Acer V66LA motherboard. https://theretroweb.com/motherboards/s/acer-v66la
It is running a 450 Mhz Pentium II with a clean installation of Windows 98SE. The board has three PCI and four ISA slots available on a riser card, but no AGP port. It lacks built-in LAN and a sound chip but it does have an on-board Ati Rage Pro video adapter with 4 MB memory. Since it isn't doing a very good job with 3D games, I tried installing alternative video adapters.

My first bet was a Diablotek VAR128P-32P, an Ati Rage 128 Pro PCI card with 32 MB memory. After installing it as primary display adapter, the screen stayed blank during POST, I could get to BIOS settings, and Windows failed to start. Only after taking it out and setting the Primary display adapter option in BIOS to Onboard, I was able to start up Windows with the 128 Pro as secondary adapter, and install the drivers. Windows device manager showed the 128 Pro with the message "Multiple Display support cannot start this device. The area of memory normally used by video is in use by another program or device".
When I connected the monitor to the VGA port of the 128 Pro, I saw a text message saying that Windows had successfully initialized the adapter, and to use it with the Windows desktop, I had to adjust the settings in the Display option of the Control Panel. I wasn't able to select any alternative memory areas in the device manager or to disable the on-board Rage Pro adapter.

With the second card, an Nvidia TNT2 M64 PCI card, I was even less successful. After installing, neither the onboard Ati Rage Pro, nor the TNT2 showed anything, regardless whether I set the onboard adapter or the external card as primary display adapter.

I cleared the CMOS before installation, took out all other expansion cards first, and I tried every available PCI slot. There's a jumper on the motherboard that controls whether or not an IRQ is assigned to the display adapter. I tried both jumper settings with both cards, and with the BIOS Primary adapter BIOS option set either to Onboard or Auto, but no combination worked. The BIOS does not seem to offer any other relevant settings, although the manual (downloaded from theRetroweb.org) has a section on advanced options, which are not available in my case. AFAIK there aren't any alternative BIOS versions for the motherboard (current is V 3.2), and I didn't risk trying out any alternative BIOS'es for the Diablotek card.

Do you have any experience with installing external video cards on this Acer board? Any tips, or help? Thanks a lot!