Both Onda V975i and V819i come with Android operating systems but according to the latest reports the company will be releasing an update that will allow the users to run Windows 8.1 OS on it.
It is totally possible to run either of the operating systems on it as both Onda V975i and V819i run on x86 architecture which are supported by Windows 8 and Android OS.
Onda V819i
Display: 8-inch display with a resolution IPS WXGA (1280 x 800 pixels),
Processor: 4-core, 64-bit Intel Atom Bay Trail-T
RAM: 2 GB,
NAND Memory: 16 GB + micro SD slot,
Camera: 2-megapixel,
Camera: 5-megapixel
Communication: WiFi, Bluetooth 4.0, USB port,
Battery: lack of data,
System: Google Android 4.2.2 Jelly Bean with ONDA UI 2.0.
Onda V975i
Display: 9.7-inch display with a resolution IPS WQXGA (2048 x 1536 pixels)
Processor: 4-core, 64-bit Intel Atom Bay Trail-T
RAM: 2 GB,
NAND Memory: 32 GB + micro SD slot,
Camera: 2-megapixel,
Camera: 5-megapixel
Communication: WiFi, Bluetooth 4.0, USB port,
Battery: lack of data,
Thickness: 8.5 mm
Weight: 495 g
System: Google Android 4.2.2 Jelly Bean with ONDA UI 2.0.
The upgrade will come in the month of May. The reason is that Intel is giving away free processors to tablets based on Intel bay trail t-series.