What is OEM?
In IT support, OEM has two closely related uses:
- The maker of the system or device. Dell, HP, Lenovo, Apple, and Samsung are OEMs for their computers and phones. When a procedure says to get drivers or firmware from the OEM, it means that manufacturer's support site.
- Parts from the original manufacturer. An OEM part is made by, or to the specification of, the company that built the device. The alternative is an aftermarket, third-party, or generic part.
The term is used loosely across industries. It sometimes describes a company that makes components another company sells under its own brand. In A+ work, it nearly always means the system or device manufacturer.
OEM vs. aftermarket parts
| Factor | OEM part | Aftermarket part |
|---|---|---|
| Fit | Made for the exact model | Usually fits; quality varies by supplier |
| Cost | Higher | Lower |
| Support | Covered by the manufacturer's support and warranty process | Damage caused by the part may not be covered |
Batteries and chargers are where the difference matters most. Low-quality replacement batteries and adapters may lack proper protection circuits and can overheat or swell. Some laptops warn when they cannot identify the power adapter and may charge slowly or limit performance. Screens, keyboards, and printer toner and ink also come in OEM and compatible versions.
OEM software licensing
- An OEM Windows license is preinstalled by the PC maker and tied to the first computer it was installed on, specifically its motherboard. It cannot be moved to another computer. A retail license can be transferred to a new PC.
- Replacing the motherboard with a different model is generally treated as a new computer for OEM licensing, though a warranty replacement from the manufacturer keeps the license.
- On current OEM PCs, the Windows product key is embedded in the UEFI firmware, so Windows activates automatically when it is reinstalled on the same hardware.
- OEMs also preinstall their own utilities and trial software. Removing unwanted preinstalled software is a common setup task.
OEM drivers, firmware, recovery, and diagnostics
- Drivers. Chipset, audio, touchpad, hotkey, and power-management drivers from the OEM support site, matched to the model or service tag, often include features that generic drivers from Windows Update lack.
- Firmware. BIOS/UEFI updates come from the OEM for that exact model. Flashing the wrong file can leave the board unable to start.
- Recovery. Many OEM systems include a recovery partition or a download-based recovery tool that restores the factory image, including OEM drivers and preinstalled software. A factory restore removes user data, so back up first.
- Diagnostics. Most OEMs build hardware diagnostics into firmware or offer them as downloads. Run them before replacing parts and when opening a warranty case, which usually starts with the serial number or service tag.
OEM on the CompTIA A+ exam
OEM is not on the 220-1201 acronym list and is not named in an objective, but it runs through support scenarios. Core 1 objective 1.1 covers replacing mobile device parts with appropriate techniques, where OEM versus aftermarket parts matters, and objective 3.7 calls for appropriate printer drivers for a given operating system, which usually means the manufacturer's driver. Core 2 brings in OEM licensing and recovery partitions during installation and licensing topics. A manufacturer's driver is an OEM driver; a Windows license that cannot move to a new PC is an OEM license; a factory-reset partition is an OEM recovery partition.