Meta Muse's 2,000-tray fleet estimate rests on one hypothetical server and rough napkin math

The spec sheet came from the agent. Hoffman and Kim got it by prompting Muse to run Ubuntu commands and pass back the output ^[3]. That only works because Meta built the Runtime Cell to be inspected. David Singleton, VP of Engineering at Meta Superintelligence Labs, says the transparency was deliberate, and users can see every file from Debian system files to the Muse binaries ^[19]. The cell has its own root filesystem, while a Sentinel process outside it watches sensitive actions and credentials are stored outside as well ^[18]. For a machine users are meant to open up, I think the split is sensible. The cell still has limits. A command to query the kernel buffer failed on permissions ^[20]. Hoffman also said Muse offered to set up SSH into its private VM ^[21].

Meta's September 8 launch announcement describes a dedicated cloud computer for each user, and Meta has not disclosed per-user specifications, server density or fleet capacity ^[13][14]. John Gruber wrote that Muse is "groundbreaking technically (each user gets their own entire persistent Linux VM running in Meta's cloud)" ^[23].

The Tom's Hardware estimate sits on one assumed box, and that box runs out of CPU and memory at exactly the same point. Two vCPUs per sandbox into 512 vCPUs is 256. Eight gigabytes into 2,048GB is also 256, because the server and the sandbox both work out to 4GB per vCPU ^[1]. Dividing 500,000 users by 256 gives about 1,953 trays, rounded to 2,000 ^[9]. "This is just some rough napkin math; don't take it as law," Jake Roach wrote in the Tom's Hardware report ^[10]. He allowed that Meta may run several chip types and carry configuration overhead ^[11].

The word "core" changes the answer by a factor of two. The Tom's Hardware headline gives each sandbox two dedicated cores, while its server math counts vCPUs ^[2][7]. RuntimeWire describes the allocation as two vCPUs ^[1]. The EPYC 9D25 has up to 128 cores, so a two-socket box carries 256 physical cores and 512 vCPUs is two per core ^[3]. If each sandbox holds two physical cores, one box fits 128 users. At that density, 500,000 users need about 3,906 trays ^[4].

In my view the per-user shape is the more useful number. Two vCPUs, about 8GB of memory and 100GB of disk is what users measured inside Muse ^[1][12]. ChatGPT's Work mode reportedly runs a VM with 15GB of RAM and more than nine CPU cores, according to The Decoder ^[22]. Its memory is nearly twice Muse's ^[7]. Muse has a free tier, and Stark Insider reported paid Power and Maximum plans at $20 and $100 a month ^[15]. According to RuntimeWire, neither the allocation nor the tray estimate reveals what Meta actually spends to run the service ^[16].