SpaceX Colossus

AI compute campus · Memphis, TN, and Southaven, MS · Formerly xAI, now SpaceXSI

Colossus was built to train SpaceXSI's Grok models and is now also a compute rental business. All of Colossus 1 runs for Anthropic, Grok trains on Colossus 2, and Google and Reflection AI rent capacity too, for about $2.3B a month in contracts.

Schematic map of SpaceX's Colossus sites in Memphis, Tennessee, and Southaven, Mississippi, colored by who uses each, with the reported Brownsville, Texas site inset THE COLOSSUS SITES, SCHEMATIC, NOT TO SCALE MISSISSIPPI RIVER TENNESSEE MISSISSIPPI MEMPHIS COLOSSUS 1Anthropic, all capacity220,000+ GPUs Paul Lowry Rd, South Memphis COLOSSUS 2Grok training, Reflection AI,part of Anthropic MINIHARDBeing built Tulane Rd, Whitehaven POWER PLANT41 turbines, ~1.2 GW Stanton Rd, Southaven MACROHARDRRThird building Stateline Rd, Southaven BROWNSVILLE, TXAbout 444 acres, reporteddata center site INSET, NOT ON MAP
Owner
SpaceX (SPCX)
Memphis-area buildings
4, plus a power plant
Anthropic commitment
Up to $84.5B
Colossus 2 IT power
About 946 MW
Rental contracts
About $2.3B a month
Hub
Deployments

The sites

Four Buildings in Memphis and Southaven, With a Fifth Site Reported in Brownsville

Colossus is a family of sites on both sides of the Tennessee-Mississippi line in south Memphis, plus a reported site in Brownsville, Texas, near SpaceX's Starbase.

Colossus 1 opened in a former Electrolux plant in 2024. Colossus 2 followed in Whitehaven, with its gas power plant across the state line in Southaven. Minihard is going up beside Colossus 2, and MACROHARDRR, a third building, is in Southaven. In Brownsville, about 444 acres near the Port of Brownsville were removed from city limits in August 2026 for a SpaceX project the company has not described; SemiAnalysis reports it is a data center, and other reports place data center construction near Starbase on Texas Highway 4.

  • Anthropic
  • Shared: Grok, Reflection AI, Anthropic
  • SpaceXSI only
  • Power
  • Not disclosed or planned
The Colossus sites
SiteGPUsPowerUsersStatus
Colossus 13231 Paul Lowry Rd, Memphis, TNMore than 220,000 Nvidia H100, H200 and GB200More than 300 MW per the Anthropic announcement; the S-1 reportedly lists about 130 MWAnthropic, all capacity since May 2026Operating
Colossus 25420 Tulane Rd, Memphis, TNAbout 110,000 GB200 plus 440,000 GB300 running, per Musk; S-1 lists about 440,000 GPUsAbout 946 MW of IT, Epoch AI estimate; 1 GW company ratingGrok training, Reflection AI, part of Anthropic's contractOperating and expanding
Minihard5414 Tulane Rd, Memphis, TNAbout 220,000 GB300 planned, in a denser layoutNot disclosedNot disclosedUnder construction; 312,000 sq ft, four stories; $659M permit value
MACROHARDRR2400 Stateline Rd W, Southaven, MSNot disclosedNot disclosed; the Colossus sites together target almost 2 GWNot disclosedStatus not disclosed; more than $20B announced
Southaven power plant2875 Stanton Rd, Southaven, MS-41 permanent turbines approved, about 1.2 GWPowers Colossus 2Temporary turbines being removed
Brownsville site (reported)Near the Port of Brownsville, TXNot disclosedNot disclosed; job postings seek cooling and turbine engineersNot disclosedAbout 444 acres de-annexed August 2026
Atlanta1025 Jefferson St NW, Atlanta, GAAbout 11,000 H100 and 1,448 A10017 MWSpaceXSIOperating

Company GPU and power figures run ahead of independent estimates. Epoch AI counts about 946 MW of IT power at Colossus 2 as of June 2026 and projects about 1.5 GW by February 2027.

Who rents it

Anthropic, Google and Reflection AI Rent Colossus Compute

SpaceX reports compute rental as part of its AI segment. The contracts below add up to about $2.3B a month.

Compute customers on the Colossus sites
CustomerSiteCapacityTermsSince
AnthropicColossus 1 (all) and part of Colossus 2About 325,000 GPUs across both$1.25B a month through May 2029, about $45B in the S-1; up to $84.5B in Anthropic's prospectus; 90-day terminationMay 2026
GoogleNot disclosedAbout 110,000 GPUs$920M a month, October 2026 to June 2029October 2026
Reflection AIColossus 2GB300 capacity, GPU count not disclosed$150M a month, up to $6.3B through 2029July 2026
CursorNot disclosedNot disclosedSpaceX acquired Cursor in August 2026April 2026

SpaceX's S-1 describes the Anthropic agreements as covering Colossus and Colossus II at about $45B. In September 2026 Reuters reported that Anthropic's confidential IPO prospectus puts the commitment at up to $84.5B through 2029, still mostly cancelable on 90 days' notice. The Pentagon is in talks for capacity, the Wall Street Journal reports.

Where Grok lives

Grok Trains on Colossus 2

  • Grok 4 was trained with reinforcement learning on Colossus 1, described by SpaceXSI as its 200,000-GPU cluster.
  • Newer training moved to Colossus 2: Musk posted on May 8, 2026 that new Grok models were training there, on GB200 and GB300 systems powered from Southaven.
  • Grok inference, the serving of Grok to users, runs at sites SpaceX has not disclosed. A 17 MW site in Atlanta also runs SpaceXSI workloads.
  • Grok in Tesla vehicles, built into new Teslas since July 2025 and able to control car hardware by voice since the 2026.26 update in July 2026, processes conversations on SpaceXSI servers, not in the car; it needs the AMD Ryzen infotainment computer and a data connection. Which cluster serves it, and whether it runs in virtual machines, is not disclosed.

Colossus 1, built in 122 days to train Grok, now trains Anthropic's models instead.

The names

Colossus, Macrohard, Minihard and SpaceXSI

The company

  • February 2, 2026: SpaceX acquires xAI in an all-stock deal.
  • June 12, 2026: SpaceX lists on Nasdaq as SPCX.
  • July 6, 2026: xAI becomes SpaceXAI.
  • October 4, 2026: SpaceXAI becomes SpaceXSI, SpaceX Super Intelligence; the legal entity is reportedly still SpaceXAI LLC.

Macrohard

  • The software company: announced in August 2025 as a "purely AI software company" built to simulate firms such as Microsoft; Business Insider reported in March 2026 that the effort had stalled.
  • The roof: "MACROHARD" was painted across Colossus 2's roof in October 2025.
  • MACROHARDRR: the third building, in Southaven, named by Musk in December 2025.

Minihard

Musk named Minihard in July 2026: a fourth building at 5414 Tulane Rd beside Colossus 2, built to hold about 220,000 GB300 GPUs in a smaller, denser building than its neighbor. Its construction permit, filed in March 2026, values it at $659M.

Colossus 3

SpaceX has not used the name. Wikipedia applies it to MACROHARDRR in Southaven; social media applies it to the Brownsville site.

Power

Gas Turbines First, Then a Permanent 1.2 GW Plant

  • Colossus 1: about 150 MW from Memphis Light, Gas and Water (MLGW) on the TVA grid, up to 15 permitted gas turbines (about 247 MW) through January 2027, and 168 Tesla Megapacks.
  • Colossus 2: Mississippi regulators approved 41 permanent turbines, about 1.2 GW, at the Southaven plant in March 2026. Temporary turbines, reported at 27 to 69 units, are being removed between August 2026 and July 2027.
  • Disputes: the NAACP sued over the turbines in April 2026; the Justice Department moved to dismiss the case in June.
  • Solar: a 30 MW solar farm is planned beside Colossus.

See Onsite Gas and the energy models of the largest US campuses.

The stack inside

Nvidia Rack-Scale Systems on Liquid, Fed by Gas

The Colossus stack by layer
LayerAt ColossusMore
ChipsNvidia H100, H200 and GB200 at Colossus 1; GB200 and GB300 at Colossus 2Chip depth at SemiconductorX
Server and rackSupermicro liquid-cooled racks at Colossus 1; GB200 and GB300 NVL72 rack-scale systems at Colossus 2See the GB200 NVL72 supplier ring
NetworkNvidia Spectrum-X Ethernet at Colossus 1, Nvidia says; Colossus 2 fabric not disclosedNetwork and Fabrics
CoolingLiquid-cooled racks; 217 air-cooled chillers reject about 412 MW of heat at Colossus 2, Epoch AI countsDirect-to-Chip Cooling
PowerGrid from MLGW and TVA, gas turbines, 168 Tesla Megapacks at Colossus 1; the Southaven gas plant for Colossus 2Onsite Gas

Record

Dataset Record

Dataset
Colossus sites and compute contracts; Colossus rows also in us_ai_campuses.csv
Sources
SpaceX S-1 and SEC filings, Not a Tesla App, Digital Citizen, Epoch AI, Mississippi Department of Environmental Quality, Shelby County Health Department, DatacenterDynamics, TechCrunch, Fortune, Engadget, The Next Web, Action News 5, Mississippi Free Press, San Antonio Current
Last verified
October 2026