Windows Defender Sandbox?

Is Windows Defender Sandbox mode enabled by default on v1809?

The sandbox feature is available in Windows 10 version 1703 and above, but it is disabled by default.

Do you have it enabled? If so, how does it impact performance?

Yes you can use Windows Sandbox if you want to but you have to enable it from Control Panel --> Programs and Features --> Turn Windows features on or off.

win10freak said:

Do you have it enabled? If so, how does it impact performance?

If you enable and don't use it I can't notice the difference. Theoretically disk I/O may be marginally slower as this is then abstracted - same as if you enable Hyper-V role.