Nexus 6 is slower than the Nexus 5 thanks to security measures

You'd expect a new phone to be at least a bit faster than the one it replaces, but the Nexus 6 is actually a good deal slower than the Nexus 5 thanks to a form of security encryption enabled in the phone as standard.

As found in benchmarks undertaken by AnandTech, the Nexus 6 is more sluggish than the Nexus 5 in terms of the speed at which data is written to the internal memory.

While it doesn't mean the actual processors of the new phone are slower, the impression it leaves in general use is of a less snappy device.

At first, this performance issue was rumoured to be down to lower-quality eMMC memory chips used in the Nexus 6 by Motorola, which produces the phone for Google.

However, these benchmarks show that it's all down to FDE: full device encryption, which has been an option in Android for years, but has only just become the standard for devices shipping with Android 5.0.

Glitch in the system

Anandtech notes a "62.9% drop in random read performance, a 50.5% drop in random write performance, and a staggering 80.7% drop in sequential read performance."

This jams up the gears on the Nexus 6's system, negating some of the benefits of its powerful Snapdragon 805 CPU and resulting in day-to-day performance that feels worse than the Nexus 5's.

Spending £500 on a phone that feels more sluggish than a £250 one isn't going to make anyone happy.

To prove FDE is the issue, a non-encrypted version of the Nexus 6 was also tested, and performed far better than the Nexus 5, not just the encrypted Nexus 6.

Until now full device encryption has been offered as a super-secure extra security option in Android for those who want to make sure their data isn't going to be pilfered - it's encrypted until you unlock the phone with your passcode.

This highlights a key issue with enabling FDE as standard: it's a bit pointless for those people who don't even put a passcode on their Nexus 6. It's a performance tax with no benefit.

• Read our in depth Nexus 6 review