Synology DS411Slim and encryption: major negative impact also in reading.

A few days ago I created an encrypted volume on my DS411Slim and reported a major degradation in writing speed.
I hoped that reading was maintained in the original ballpark, but this is not the case.
12.5MB/s is all I can get and is very bad in comparison with the former 70+ MB/s

Since my first post I did some research and, according to Synology’s own tests, I should get about twice the current speed.

I’ll give a try at a more recent version of DSM (I’m on the stock 3.2) to see if it provides better performance.
I’m usually a bit reluctant to update the firmware of working devices, but the opportunity of getting better performance on the 50GB backups is pushing me in this direction.

Synology DS411Slim and encryption: an unpleasant surprise

Some time ago I built an encrypted volume on my small nas from Synology and today I did the first real test.
I’m backing up an entire volume with Disk2VHD, a nice free utility from Microsoft’s Sysinternals tools to make online volume snapshots.
I did this in the past several times from the same machine on a regular non-encrypted volume on the same nas obtaining about 37 to 40 MB/s of sustained writing speed.

Given the hardware encryption engine included the nas I was expecting a similar performance with the encrypted volume but this is not the case.
The speed is down to 7MB/S, a sharp 80% loss.
I’m running DSM 3.2
I wonder if this is common/expected or not.
The backup will have to be again a nightly activity until I find a way to get back the high-speed when using the encryption 😦

Update: I’ve had the opportunity to test large reads too and it’s not looking good