From the Microsoft Tip of the Day Blog:
Generation 2 VMs replace a large number of emulated devices with resource efficient synthetic devices. Here is a list of Generation 1 devices that you will not find in a new Generation 2 VM.
- BIOS
- COM Ports
- DMA Controller
- Floppy Controller
- i8042 Keyboard Controller
- IDE Controller
- Legacy NIC
- PCI Bus
- Programmable Interupt Controller
- Programmable Interupt Timer
- PS/2 Keyboard
- PS/2 Mouse
- S3 Video
- Super I/O Device