how to choose between mobile options

[ebridges]

On http://www.webpagetest.org what is the difference between these two options for testing on a Nexus 5 using Chrome?

• choosing "Nexus 5 - Chrome" under the "Browser" dropdown versus ticking the checkbox "Emulate Mobile Browser"
• selecting "Nexus 5" on the "Chrome" tab under "Advanced Settings"
  

Is the first case running the test on a physical device, and the second running it on an Android emulator?

Thanks

[andydavies]

Nexus 5 - Chrome is a real Nexus 5, the emulated mobile browser is desktop Chrome emulating mobile viewport characteristics.

The desktop Chrome emulation is likely to be faster than a real mobile device but will churn through tests faster, and of course is available in more geo-locations