Concurrent tests runs and Browser VU instance allocation

Grafana k6 k6-browser
1

Hi,

I need some help, I looked at the public documentation but I couldn’t find answers to this two questions:

  1. Concurrent test runs — how many test runs can execute simultaneously in one project/org, per tier? Free tier appears to serialise them; the limits page doesn’t mention this dimension at all.
  2. Browser VU instance allocation — are browser VUs scheduled on dedicated load generator instances, or do they share instances with protocol VUs from other scenarios in the same test?

Same script, same target. With 3 browser VUs and no protocol load: sdk_loaded p95 = 582 ms. With 10 browser VUs alongside 90 protocol VUs in one test: 4817 ms. Resource Timing shows the request is issued at 4588 ms while server wait is 5 ms and transfer 17 ms — the browser doesn’t begin fetching for ~4.5 s. Is this expected contention on a shared generator instance, and does a paid tier isolate browser VUs or permit concurrent test runs so load and browser measurement can be separated?