Mobile Devices
What to know
Laptops and mobile devices pack many components into one chassis, so questions usually hinge on knowing which part is field-replaceable and which parts are compatible. Laptop RAM is SO-DIMM (or soldered in thin-and-light models) and must match the DDR generation; DDR3, DDR4, and DDR5 are not interchangeable because the notch position and voltage differ. Storage has largely moved to M.2, which may be SATA or NVMe (PCIe). The slot looks the same, but a SATA-only slot will not accept an NVMe drive and vice versa. Displays contain an LCD or OLED panel, a backlight, and a digitizer on touch models; older CCFL panels used an inverter, which LED backlights do not.
Connectors and accessories are fair game: USB-C, Thunderbolt, Lightning, and microUSB, plus docking stations versus port replicators (a dock usually adds power and extra ports; a replicator is simple port expansion). Wireless features include NFC, Bluetooth pairing, hotspot/tethering, and MDM enrollment.
Traps. Li-ion batteries have no memory effect, so “fully discharge before charging” is wrong; a swollen battery is a safety issue and must be replaced, not punctured. POP3 (110/995) downloads mail and typically removes it from the server, while IMAP (143/993) keeps folders synchronized - the giveaway is “multiple devices must see the same mailbox state.” SMTP (25/587) only sends.
Rule of thumb. No display but the machine powers on and fans spin points to the display/backlight or RAM; a device that works on AC but dies on battery points to the battery or charging circuit.
Worked example. A user cannot add a corporate account that must show the same read/unread state on phone and laptop: choose IMAP (or Exchange/MAPI), not POP3.