How it works

GaN changes the switch inside the brick, not the USB-C handshake. A charger chops wall AC into the DC profile your laptop asked for. Silicon MOSFETs have done that job for decades. They work. They just waste more energy as heat and need bigger magnetics (the transformer and inductors) to keep switching losses in check.

GaN transistors (usually lateral HEMTs, high-electron-mobility transistors) use a gallium nitride and aluminium gallium nitride interface instead of a doped silicon channel. They have no silicon-style body diode, so they skip reverse-recovery losses, and they can switch at much higher frequencies. Higher frequency means smaller magnetics. Less waste heat means a smaller heatsink. That is why a 65W GaN cube can replace the laptop brick that used to fill a coat pocket.

Wattage still sets speed. A 65W GaN charger and a 65W silicon charger with the same USB-PD profile will charge the same laptop at the same rate. GaN's job is packing those watts into something you will actually carry.

When it matters

It matters once you leave 20W phone bricks and start charging a USB-C laptop, or you want one multi-port block for a laptop plus a phone. Below about 30W, silicon is still cheap and the size gap is small. At 65W and up, GaN is how you get laptop watts without the old power-brick bulk. Above 100W, almost every travel-sized charger on the market uses GaN because silicon would run too hot in that volume.

GaN does not fix a thin cable. Above 60W the cord still needs an e-Marker chip, the same rule spelled out on the USB-PD page. Pair the brick with a 100W-rated USB-C cable or you will silently cap near 60W.

If you only charge a phone overnight at the nightstand, you do not need GaN. You need it when the brick has to travel or share ports.

These two Anker bricks are already in the site catalog and show the size-versus-ports trade.

The Anker 715 (Nano II 65W) is the one-port GaN II cube. Anker rates it at 20V / 3.25A (65W max), about 1.65 x 1.42 x 1.74 inches, with a foldable plug. It sits around $30 as of this writing. The usual complaint is the missing cable and the single port: you cannot charge the laptop and a phone at once. View on Amazon if you want one brick for a MacBook Air or a 13-inch Pro and nothing else.

The Anker 737 (GaNPrime 120W) is the three-port version (2x USB-C plus USB-A). One USB-C port can do 100W (20V / 5A). The 120W total is a shared pool, so two laptops will each get less than the single-port max. Reviewers consistently call out the size: it is still a fist-sized block next to a Nano II. Street price has usually sat around $60 to $65. View on Amazon when you want laptop plus phone from one wall wart.

Anker 715 Nano II Anker 737 GaNPrime
Ports 1x USB-C 2x USB-C + 1x USB-A
One-port max 65W 100W
Shared total 65W 120W
GaN generation GaN II GaNPrime
Size about 1.65 x 1.42 x 1.74 in, foldable plug about 80 x 43 x 32mm, ~187 to 193g
Typical street price about $30 about $60 to $65
Catch no cable in the box, one device at a time shared watts, bulky for a travel brick

For wattage picks, airline rules, and which brick to buy, read The Best USB-C Chargers for Your Laptop and Phone. For the handshake that actually moves those watts, see USB-PD.