Elon Musk has also embraced the C language. The large model training stack has abandoned JAX, accelerating by an order of magnitude.

Without using JAX, SpaceX is training new models with a brand - new stack written in C language.

Moreover, Elon Musk himself admitted that Grok 5 is already using this new stack.

According to Musk, this new stack can increase the training speed of large models by an order of magnitude.

Next, the stack for the inference part will also be rewritten in C language.

Meanwhile, Musk didn't forget to show off his GB300 and recruit talents for SpaceX:

Please note that I'm posting this message to encourage those who want to achieve excellent performance from hardware to join SpaceX.

Colossus II May Also Be Rented Out

Efficiency is improving, and computing power is expanding.

Musk is not only competing for efficiency at the software level but also achieving remarkable results on the hardware side.

SpaceX is building the next - generation supercomputer cluster codenamed Colossus II, with a total power of 1 gigawatt and a cost of about $17 billion.

In comparison, xAI spent $3 to $4 billion on building Colossus I, and Colossus II has directly increased the scale by an order of magnitude.

While expanding computing power, SpaceX is also seriously considering how to turn this computing power into money.

In the latest public prospectus, AI infrastructure is clearly listed as an important business segment of the company, on par with rocket launches.

Musk also revealed that SpaceX is in talks with other companies about similar computing power leasing cooperation, and an orbital data center is also in the planning.

From rocket manufacturing to computing power rental, the core asset of this new track is the Colossus series of clusters.

Colossus II may also be rented out in the future, but Musk's attitude is thought - provoking.

He said that he "does not commit" to long - term leasing and can take it back at any time, all depending on his own computing power needs.

The implication is clear: external customers will always come after the company's own business.

The Computing Power Agreement with Company A Is Only for Six Months

This "taking it back at any time" is not just empty talk.

Some time ago, xAI rented Colossus to Anthropic at a price of $45 billion per year, and it was rumored that the contract was for three years.

It sounds like a sure - fire big business, but Musk quickly poured cold water on it in a tweet.

Musk clarified that SpaceX has never promised to rent out Colossus for the long term. The existing one is only a 180 - day lease, and either party can cancel it with a 90 - day notice after the lease expires.

He also specifically pointed out that choosing the short - term clause was an active request from SpaceX, not the intention of Company A.

More precisely, according to SpaceX's prospectus, the actual terms of the agreement are as follows:

Anthropic pays $1.25 billion per month, and the contract is set to expire in May 2029, with a potential total amount of over $40 billion.

But the prospectus also clearly states in black and white that either party can terminate the agreement with a 90 - day notice to the other party.

This puts Company A in a rather delicate situation. For training cutting - edge large models, computing power is the lifeblood. Once Musk wants to cut off the supply, Anthropic only has a 90 - day window to maneuver.

More importantly, the competitors vying for computing power with Company A are actually Musk's own companies. The Grok series needs training, and Tesla's autonomous driving business also has a rapidly growing appetite for computing power.

Once the internal demand is tight, external tenants have to take a back seat.

So, to some extent, what Company A bought at a high price is an admission ticket that may be confiscated at any time.

However, Musk didn't completely close the door. He said that he wouldn't let them get into trouble and would provide a reasonable exit arrangement.

Renting out computing power externally, building a training stack on its own, and expanding the supercomputer cluster are being promoted simultaneously. SpaceX's AI computing power business is booming.

As for who will be the long - term customer and who will only be a temporary tenant, it still depends on Musk himself.

Reference Links:

[1]https://www.businessinsider.com/elon-musk-spacex-anthropic-escape-hatch-2026-5

[2]https://x.com/JohnTinsman/status/2059654405964657093

[3]https://x.com/elonmusk/status/2059884150187053488

This article is from the WeChat official account "QbitAI", author: Keleixi. Republished by 36Kr with permission.