When you buy a wireless mouse or keyboard, you can choose either Bluetooth or wireless peripherals that communicate through a USB dongle over radio frequencies (RF.) USB-RF has less latency, in our experience, but Bluetooth has its advantages.
Which Is Faster?
Latency is critical with any keyboard or mouse. You want your input to be reflected onscreen as quickly as possible---especially if you play games dependent on twitch reflexes, like first-person shooters.
According to Razer, USB-RF offers lower latency. The company told us while Bluetooth Low Energy (BLE) devices can achieve latency as low as 1.3 ms, USB-RF beats that at a flat 1 ms. The Razer spokesperson even told us the difference in speed is why they only offer USB-RF devices. The company focuses on gaming, so it makes sense it would choose the fastest option.
Logitech promises a similar, 1 ms wireless speed with its Lightspeed mice, but it uses a proprietary form of 2.4 GHz communication. According to The Verge, this meant fewer interference issues than encountered with other wireless mice (like Razer) that use the standard form of 2.4 GHz communication.
It's worth noting that wireless mice and keyboards aren't using the same technology as your wireless Wi-Fi router, which operates over a completely different frequency.
Which Is More Compatible?
Latency isn't everything. USB-RF mice require a USB dongle, and not all devices have those traditional, full-size USB (also called USB-A) ports.
Bluetooth is more compatible with more devices because you can use its peripherals with devices that don't have USB-A ports. As USB-C continues to grow, owning a wireless RF mouse or keyboard will become more complicated. You can buy a USB-C mouse, but what do you do when your laptop only has USB-C ports, and your desktop doesn't have any? You can either get an adapter (which is one more part to lose) or a mouse that comes with both USB-C and USB-A.
As for keyboards, we couldn't find any wireless USB-C options from any well-known manufacturers.
A Bluetooth peripheral doesn't have that problem; it's completely wireless. Even if your desktop doesn't have Bluetooth, you can solve that problem with a Bluetooth dongle. And because it remains attached to your desktop, you don't have to worry about losing it.
Some devices, like the iPad Pro, don't have traditional USB ports at all and either have, or are starting to adopt, mouse support. If you want to use a mouse on a tablet, a Bluetooth model will likely work best. Even tablets with USB ports, like the Surface Pro, typically work with Bluetooth peripherals.
Which Is Easier to Set Up?
When it comes to simple set up, peripherals that use a wireless dongle are the clear winner. You plug the dongle in, and the operating system should detect the new device and add the driver automatically. Typically, you're up and running in just a few seconds. One dongle can also connect both a keyboard and mouse if they're purchased together or, in some cases, from the same manufacturer.
A Bluetooth mouse or keyboard, on the other hand, requires more steps. First, you put everything in pairing mode, and then wait for your laptop or tablet to talk to the mouse or keyboard. You'll have to pair the mouse and keyboard individually if you have both. And when you move to the next device, you'll have to go through the whole process again.
After the initial set up, though, Bluetooth takes the crown for continuous ease of access. Ready to move from your PC to your tablet on the go? Just take your tablet and keyboard or mouse far enough away from your PC to lose the connection. The keyboard or mouse should automatically pair with your tablet. Alternatively, you can turn off Bluetooth on your PC to force the process.
With a USB-RF peripheral, you have to remove the dongle from your PC and plug it into the next device you want to use. If you're traveling, it's easy to lose. Sometimes, there's a spot in the mouse to store a dongle, but that's not always the case. And some keyboard mouse combos, like the Microsoft Sculpt Ergonomic Keyboard and Mouse set, are permanently associated with a single dongle. If you lose it or it fails, you have to replace the entire set.
Choose Both
If you're unsure what you need now or what you might need in the future, you can choose both! Logitech offers keyboards and mice, like the K375s Keyboard and M720 Triathalon Mouse, that are both Bluetooth and RF capable. Some of the mice even have a dedicated button to switch more easily between paired devices.
Similarly, you can connect Razer's Atheris Wireless Mouse either through a USB dongle or Bluetooth.
A mouse or keyboard capable of both RF and Bluetooth means you can use your peripherals with all your devices without needing to unplug a dongle. Plug the dongle into one device (preferably, one that isn't Bluetooth capable) and pair your mouse or keyboard over Bluetooth with the rest.
Just keep in mind, when you use the Bluetooth connection, you won't get the lower latency speeds of USB-RF. Similarly, when you connect over USB-RF, you lose Bluetooth's advantages.