Direct-answer intro
The GeForce 4 Ti 4600 often fails to boot past POST due to AGP voltage mismatches and BIOS settings on older Pentium III-era motherboards.
GeForce 4 Ti 4600 Won't Boot Past POST: AGP Voltage and BIOS Field Guide
Editorial intro
During the AGP era, GPUs like the GeForce 4 Ti 4600 had strict voltage and compatibility requirements that many early Pentium III motherboards struggled to meet. This guide covers why the Ti 4600 fails POST, correct AGP voltage usage, BIOS chipset support, and common troubleshooting steps including BIOS flashing and power supply checks.
Key Takeaways
- Ti 4600 requires 1.5V AGP slot or compatible voltage keys.
- Many Pentium III boards only support 3.3V AGP, causing no POST.
- BIOS revisions vary in chipset compatibility with certain AGP GPUs.
- PSU wattage and CMOS battery health impact startup success.
Why does the GeForce 4 Ti 4600 fail POST on some Pentium III boards?
The Ti 4600’s 1.5V keying does not physically fit in 3.3V-only AGP slots, common in older Pentium III systems. Even in so-called universal AGP slots, voltage may not be properly supplied, causing failure to boot.
What AGP voltage does the Ti 4600 actually need (1.5V vs 3.3V keys)?
The Ti 4600 is a 1.5V card and requires a 1.5V AGP slot key to avoid damage and ensure proper operation.
Which motherboard chipsets play nicely (i815 / i845 / KT266A / nForce2)?
Chipsets like Intel i815 and i845, VIA KT266A, and Nvidia nForce2 generally support 1.5V AGP cards reliably.
Spec table: Ti 4200 vs Ti 4400 vs Ti 4600 vs FX 5900
| Model | Release Year | AGP Voltage | VRAM | Clock Speed |
|---|---|---|---|---|
| Ti 4200 | 2002 | 3.3V | 64MB | 250 MHz |
| Ti 4400 | 2002 | 3.3V | 128MB | 275 MHz |
| Ti 4600 | 2002 | 1.5V | 128MB | 300 MHz |
| FX 5900 | 2003 | 1.5V | 128MB | 400 MHz |
Compatibility table: chipset / AGP version / known-good driver
| Chipset | AGP Version | Driver Support |
|---|---|---|
| i815 | AGP 2X | Good |
| i845 | AGP 4X | Good |
| KT266A | AGP 4X | Good |
| nForce2 | AGP 8X | Good |
How to flash a working BIOS to a Ti 4600 with NVFlash
Instructions on finding and flashing a stable BIOS version to ensure compatibility and bubble-free operation.
Common no-POST patterns: PSU wattage, CMOS battery, capacitor recap
Low power supply output, dead CMOS battery, or swollen capacitors can cause startup failure regardless of GPU.
When to use a GeForce 3 Ti 200 instead for stubborn boards
Older hardware with persistent issues may benefit from a GeForce 3 Ti 200, which has wider compatibility.
Bottom line
Understand your motherboard’s AGP voltage support before upgrading. The Ti 4600 suits boards with 1.5V AGP slots; otherwise consider alternatives.
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Sources
- https://www.nvidia.com
- https://www.techpowerup.com/gpu-specs/geforce-4-ti-4600.c172
- https://www.vogons.org
Closing meta
Published April 2026. Updated as hardware and BIOS revisions evolve.