Cerebras Fires Back at Short Sellers: Admits Chips Require 'Idle Time,' but Two-Year Obsolescence Is Pure Nonsense

Beating AI News Flash: Cerebras CEO Andrew Feldman published a lengthy article responding to short-seller Culper Research's questioning of wafer chip lifespan. Culper previously alleged that Cerebras has not truly solved the problem of chip thermal expansion and contraction, and can only keep the wafer continuously performing ineffective computations even when idle to avoid damage caused by temperature changes. The resulting high power consumption may also cause the chip to become unusable in about two years.

Regarding "ineffective computations," Feldman does not deny it. Cerebras's chip is as large as an entire wafer. If some areas run at full power while others suddenly stop, uneven heating and cooling may deform the wafer and the connection board, or even damage the connection points. Keeping some areas performing ineffective computations can slow changes in power consumption and maintain uniform temperature. The chip's electrical connections can also bend, and the cooling plate contact surface can slide, so that different materials do not pull against each other when they expand due to heat. Nvidia's B300 also adopts a similar power-smoothing design.

Based on high idle power consumption and GPU service life, Culper estimated that Cerebras wafers can only be used for about 1.4–2.3 years. Feldman believes this calculation confuses the service life of the equipment with the actual lifespan of the hardware. A GPU may be replaced after five or six years because its performance has fallen behind, but that does not mean it can only work for five or six years. To judge whether a chip will age prematurely due to high temperatures, the key is to look at the actual operating temperature.

The TSMC reliability certification conditions published by Cerebras show that the wafer can operate continuously for 10 years at 105°C. The average temperature of deployed CS-3 wafers is below 65°C, with a maximum not exceeding 85°C. According to thermal aging model calculations, even if maintained at 85°C at all times, the wafer's theoretical heat-resistant lifespan is about 33 years. Since the CS-3 was launched in 2024, less than 0.5% of deployed wafers have been retired.

Culper also alleged that the connection material Cerebras claims to have developed in-house actually comes from external supplier Paricon. Feldman denies this statement, saying that the company has never delivered to customers any system using that company's PariPoser material.

Cerebras's draft listing prospectus in December last year listed the estimated useful life of computer equipment as 1.5–3 years, while in April this year it listed "data center and computer equipment" as 3–5 years. The longer the depreciation period, the lower the equipment cost recorded each year, and the higher the book gross margin may be. Feldman's explanation is that the original equipment was mainly for R&D personnel testing, and now it also includes cloud service equipment used for long-term operations, so the useful life was adjusted.