Cerebras Systems ' monster debut on Thursday didn't just place it among tech's biggest-ever IPOs — it was a crystal clear signal of unstoppable demand for chips to power AI, as tech giants scramble to find alternatives to the costly, sold-out graphics processing units made by Nvidia . Cerebras closed its first day trading on Wall Street with a market cap just below $100 billion, putting it near the few companies to close above that mark, such as Facebook-parent Meta and Alibaba . The stock traded lower on Friday , its first full day of trading. Here's what you need to know about this hot Nvidia competitor. Cerebras makes a different type of chip than the classic Nvidia GPU, and it's the size of a dinner plate. "We build the biggest chips in the semiconductor industry," Cerebras CEO and Co-Founder Andrew Feldman told CNBC on Squawk Box Thursday.…