you can leave this setting as is since vvvv will always chose the best setting available on your graphiccard. still you can change it for debugging reasons.
this setting can be disabled to improve performance. if you observe flickers with the VideoTexture (EX9.Textures) ? node turn it back on.
Outputs
Status - mainly for debugging to see if settings made on the devices have been accepted
Caps - shows some of the graphic cards capabilities
A Word about Manually Handled Devices
every Renderer (EX9) node needs to be associated with a device. this connection is in fact handled internally by vvvv and in most cases you'll not need to know anything about the existence of "devices".
however, you can also manage devices manually. as soon as you have created a Device (EX9 Manual) node a manual device is available for renderers to use. on a Renderer (EX9) notice the "Device" configuration pin when viewed with an inspektor. this pin defaults to -1 but can be set to positive values (starting with 0) to associate this renderer with a manual device. the number of the manual device is denoted by the slice position this device is configured in, in the Device (EX9 Manual) node. therefore if you have two manual devices you you can choose between them by selecting 0 or 1 in a (Renderer (EX9) )) "Device" pin.
Purpose
two reasons come to mind for using manual devices:
debugging - you can create several devices even on one monitor. one with the type HAL and the other with type REF if you are so inclined.
specify fullscreen monitor - via the "Adapter" pin you specify the monitor/adapter this device is created for. note that a Renderer (EX9) associated with a certain device can only use hardware acceleration if its window is placed on the same monitor/adapter its device is created for. also when going fullscreen with a renderer note that it will go fullscreen on the monitor/adapter its associated device was created for, regardless of the position of its window.