Compute limits

Every run has a time limit and a memory limit. They protect the shared server and keep a mistake from running forever.

Per run#

A run that reaches its time limit is stopped and marked Timed out.

At once#

You may have one simulation, one synthesis and one build running at a time. A second build waits in a queue until the first finishes. The server also limits how many builds run across all users, so a build may wait briefly for a free slot.

What you can count on: the server runs two builds at once, and one account can only run one of them, so nobody can take both places. If a place is free, your build starts within a minute (measured 30 Oct 2026: 0 seconds while another account had one build running and one waiting). If both places are busy, builds start in the order they were sent, as soon as a place frees up; each build runs for at most 60 minutes.

Per plan#

Your plan includes an allowance of tool time, storage and Nelix Agent. The current numbers are on the Plan page. See Plans and allowances.

Staying inside the limits#

• Student space nearly full. Old build folders (openlane/runs) are usually the biggest; deleting one frees its space about 5 minutes later: the lab keeps a safety copy of every project that long, so a deleted build folder stops counting only after it. A 7,500-cell build keeps about 1.2 GB; on a 5 GB student space keep at most two or three. A deleted project still uses space for 7 days: open Recently deleted on the Projects page and choose Delete now, or select several (or all) and choose Delete selected, to free it at once.
• A simulation that times out is usually a test waiting for something that never happens. Check the reset and the clock.
• A build that times out may have finished the layout and been cut short in the final checks. Read the card; running it again often completes.
• Storage: the working files of each build are large. Delete projects you no longer need from the Projects page.

Large designs (from about 7,000 cells). Expect 20 to 25 minutes per build, antenna violations that need the stronger or strongest antenna repair in Build settings, and about 1.2 GB of disk per build. The lab's largest signed-off build so far is the 7,488-cell PicoRV32 (31 October 2026).

No one can tell from the code alone whether a design will fit these limits. A very wide multiplier or a large array is a risk worth noticing; the measured result of a build is the answer.