Voodoo Graphics Reborn: 3dfx's SST-1 and a 486 Gaming PC Rebuilt on an FPGA

A developer has recreated the 3dfx Voodoo Graphics accelerator in programmable logic, pairing it with a homegrown 486 CPU core to build a complete late-1990s DOS gaming PC inside a single Xilinx KV260 FPGA. The graphics project, called zSST, is a SystemVerilog reimplementation of the original SST-1 chipset; combined with the z486 CPU it forms ‘z486 XL,’ which already runs Tomb Raider through the game’s native 3dfx renderer. The design covers most of the Voodoo feature set—prepared triangles, texture filtering and mipmapping, depth and alpha tests, fog, blending, dithering, and retrace-synchronized buffer swaps—and clocks CPU and renderer together at 100 MHz. The board’s onboard DDR supplies the memory bandwidth; the older DE10-Nano lacks the logic to fit the design.

The work leans heavily on preservation efforts and openly available documentation. 3dfx released the Glide source in 1999, ahead of NVIDIA’s acquisition of its graphics assets in late 2000, and that code plus the SST-1 specification defines the behavioral target. Emulator projects like 86Box and MAME, along with Glide traces and reference screenshots from SpinalVoodoo, filled in the rendering details the spec leaves unspecified—the specification describes what registers should do, not how the original ASIC was wired.

Technically, the SST-1 is a rasterizer, not a modern GPU: the host CPU still handles transform, lighting, clipping, and projection, while the hardware interpolates pixels, fetches and bilinearly filters texels, and composites the framebuffer. The implementation mirrors the era’s transitional design, accepting IEEE floating-point vertex data but converting internally to fixed-point integer math so most per-pixel work reduces to adding precomputed increments. A deeply staged pipeline sustains the classic ‘one pixel per clock’ throughput by overlapping texturing, testing, fogging, and blending across successive pixels—the fixed-function approach that made fluid, textured 3D gaming possible in the first place.