Enthusiast Kate has developed a hardware modification for Nvidia CMP-170HX mining cards, allowing them to be upgraded to the specifications of an Nvidia A100 80GB GPU. The process involves using voltage glitching to bypass the onboard eFuse controller, which normally restricts VRAM capacity and shader modules at the factory level.
The modification utilizes a custom circuit board based on an STM32G4 microcontroller, costing approximately $8. This board intercepts PWM signals to the voltage regulators, creating glitches that force the fuse controller into a state that permits write access. This allows for the manual unlocking of physically present but disabled hardware components.
Testing showed that modified cards could achieve 80GB of VRAM and PCIe 4.0 speeds. One card reached 64GB of usable memory. Furthermore, unlocking additional shader modules resulted in FP16 FMA performance 20% higher than that of a standard A100, as the GA100 silicon contains 128 shader modules, while the A100 spec sheet lists 108.
While a CMP-170HX card typically costs between $2,500 and $3,000, a standard Nvidia A100 80GB PCIe card can reach prices of $20,000 or more. The researcher has disclosed the vulnerability to Nvidia, noting that the company cannot retroactively address the issue for hardware already in circulation.
