The G400 looks a lot like the Logitech G500 and, as its name suggests, it's in many ways a skimmed-down version of that model. However, if you're looking for this mouse's closest relation, you need to look to the MX518, once a star model in the Logitech mouse range.
In fact, the G400 can either be seen as a souped-up MX518, with a polling rate that's been boosted to 1000 Hz and sensitivity (dpi) that's been doubled, or a slightly lower-spec G500.
After all, it ain't broke, why bother fixing it?
Old-school button layout like on the MX518.
Sensitivity (dpi) can be changed on the fly.
Take a G500—an excellent mouse that's been hogging the spotlight for the last two years—replace the scroll wheel offering free-wheeling, click-round steps and horizontal clicking with a bog-standard wheel, replace the laser sensor with an LED sensor (which means you'll probably need a mouse mat), ditch the optional weights and the patterned finish and you basically get the G400.
The G400 is a basic gaming mouse in which everything has been designed to make a cheaper alternative to the G500, while still maintaining some top-end tech specs. In fact, Logitech has got rid of anything that's not strictly necessary and concentrated on basic performances. That sounds like a pretty sound idea if you ask us.
The sensor doesn't disappoint either. It tracked movements of up to 4.3 metres per second perfectly well in our tests, which is well above average. However, it couldn't quite deliver the 1000 Hz promised and it does use a fair bit of CPU power (see inset).
Big sliders are a good start but they aren't as indestructible as those on the Nova
We've got no complaints about this mouse's design or how it handles. It's nice and light and it has an ergonomically designed casing that fits neatly in your hand. We do, however, wonder when Logitech will start using better-quality sliders like the ceramic glides used in the Nova mouse.