External Clock Generation on RTX 50 Series
2 days ago
- #Hardware Mod
- #Overclocking
- #RTX 5090
- In the early days of overclocking, crystal swapping was used to change reference clocks, allowing for significant performance boosts, sometimes up to 16,000%.
- Over time, overclocking methods evolved from jumper and software controls on motherboards to GPU tools, but with RTX 50 series, limitations have increased, restricting memory clock adjustments and hidden clocks like crossbar.
- The hypothesis was to alter VRAM and xBAR clocks on RTX 5090 to push chips beyond NVIDIA's imposed limits, using the Elmor External Clock Board (ECB) for external clock generation.
- Testing the ECB on RTX 50 series GPUs revealed challenges, including signal integrity issues, as the GPU's PLL expects a sinusoidal waveform, while the ECB outputs a square wave.
- After trial and error, the best configuration involved a 20 ohm series resistor, 1800mV output, and minimum drive strength, producing a triangular waveform that allowed the GPU to post and bench effectively.
- Results showed significant performance gains, equivalent to +5467 on the memory slider in MSI Afterburner for RTX 5090 and a crossbar clock of around 2920 MHz, leading to high benchmark scores.
- A step-by-step guide for the mod includes removing the factory XTAL oscillator, using jumper wires, installing resistors, and connecting the ECB, with precautions for wire routing and signal settings.
- The mod overclocks all GPU components, similar to a BCLK OC, and requires careful frequency adjustments, with results varying based on motherboard compatibility and temperature.