Compatibility report: PS/1 2155 VLSI VL82C480 Chipset running at 40Mhz FSB

[lindoran]

Curious PS/1 with an onboard VLB VGA interface that seems to run well overclocked.
has a VLSI VL82C480 chipset
Cirrus Logic CL-GD5428 graphics in VLB
National Semiconductor PC87311 super io

FSB is set with tiny resistors on the motherboard, mine is set to 40Mhz giving the dx2 a internal clock of 80mhz

found on the retro web here:
https://theretroweb.com/motherboards/s/ibm-ps-1-type-2133a,-2155a,-2168a-type-1

Everything just works. No real issues except some glitching on very high notes in dark forces under gus mode (may be settings I haven't played with yet).

Haven't gotten out the scope yet but I think the VLB and ISA are always clocked at a certain rate regardless of the CPU FSB. Interface seems to perform well under these conditions.

did try out ianhan:sbwinfix and can confirm working under windows 95 OSR2 with stock drivers and DX5.

tested diablo1, direct audio works good - no glitching - video framerates low because game requires a pentium.