Debug Gitlab Runner performance issue

I am experiencing very slow run times on my CI. I am using Cypress to run tests on my NodeJS environment. Here are some time references:

• Local: 15 minutes (on a MBP Intel i5 4 cores and 16GB)
• Gitlab.com shared runners: 57 minutes
• Gitlab runner on a Gitlab managed Kubernetes cluster in Google Cloud Platform: 85 minutes! Machine type: n1-standard-2 -> 2 CPU + 6GB.

Questions:

• Does anybody knows which machines specs are used for Gitlab.com shared runners?
• Does the Gitlab runner has some kind of throttle? The Kubernetes cluster I am using has 2 nodes of n1-standard-2 and when I was running the test these nodes where far from being maxed. On one node CPU requested was close to 1 unit and memory requested was only 600MB. The other node seemed idle.