From SemiAnalysis, September 16:
On Site Turbines, Mississippi Expansion, Solaris Energy, Can xAI afford it?, Middle East Funding, Tesla, Talent Exodus, API revenue, Consumer Growth, RL Environment
Much has been written about xAI’s Colossus 1. The Memphis build belongs in the history books: the largest AI training cluster, erected from scratch in 122 days. With roughly 200,000 H100/H200s and ~30,000 GB200 NVL72, it remains, today, the largest fully operational, single-coherent cluster (setting apart Google, master of multi-datacenter-training).
However, Colossus 1’s ~300 MW looks modest next to the Gigawatt-scale clusters under construction by OpenAI, Meta and Anthropic. Their hyperscaler partners are happy to leverage their balance sheet and win the market by throwing dollars at it.
Was xAI’s prowess a one-time wonder? Today we will publicize some data from our industry leading datacenter model over the last year that is accessible to clients. This is the our same proprietary data that called the Oracle deals many months ahead of the announcement.
Short answer: no. xAI is still squarely in the frontier-AI race and is positioned to leapfrog most rivals again on compute. By our estimates, its total datacenter capacity for a single training cluster will surpass Meta Superintelligence and Anthropic by Q3 2025. The datacenter capacity will be ready for the GPUs to be moved in to create the largest single datacenter in the world, yet again. xAI has to raise the capital for those GPUs, but they have the allocations from Nvidia to have it fully training large scale models early next year.
Elon came up with a new genius trick to beat rivals at time-to-market. Colossus 2 will be an even more impressive achievement than xAI’s first cluster. Let’s dig in.
The first half of this report will dig into the Colossus 2 prowess. The second half will discuss Grok models, our mid-to-long term thoughts on xAI, and the unique RL method xAI is using that may lead them to leapfrog OpenAI, Anthropic, and Google....
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Colossus 2: from zero to 200MW in six months
The Colossus 2 project was kicked off on March 7th, 2025, when xAI acquired a 1m sqft warehouse in Memphis, and two adjacent sites totaling 100 acres. By August 22nd, 2025, we count 119 air-cooled chillers on site, i.e. roughly 200MW of cooling capacity. That’s enough to power roughly 110k GB200 NVL72. And an Elon tweet shows some racks were already installed in July.
xAI built in six months what took 15 months for Oracle, Crusoe and OpenAI!
....MUCH MORE
