There are several ways to find out what model your motherboard is:
- Reboot and read the POST screens
- Reboot and enter the BIOS
- Look for a sticker or label on the ourside of the case. Dell put “service tag” numbers on all their machines and you can references those on Dell’s support site.
- Download free software like CPUZ, which is available from HERE. This software will provide great detail on the all the hardware that does not show up in Device Manager