Undercooked.

I wanted to upgrade from a 325v2. So the next time enough space for backups (device is in the basement and serves as a backup synchronization target, so as 2nd backup memory (first memory has a RAID 1 and is smaller, kopier5 on 2nd) exists in different directories, 4 WD Red with 4 TB. Since the unit was currently on offer for 169.90 (one found directly at the manufacturer's forum, which appeared to have made a special dealer prices), I thought it nothing can go wrong.

Setting up a RAID 5 lasted about 30 hours (initial synchronizing panels). After updating the firmware, which went very fast. Since restarting necessary to the plates appear to be in operation permanently ...

As with the 325v2 there seems to be a software raid, ie disk actions the CPU load goes up. The 325v2 was associated with me with rather mixed experiences.
- No Plex
- The stupid DLNA server requires me to reboot about 1-2 days with more than 80% CPU load
- Every now and then disconnects (primarily at higher Proessorlast)

What has changed in 540?
+ 4 slots for drives with RAID 5 and up to 4 * 6GB
+ Newer CPU
- Copying is the CPU load to 66% ...
- No Plex (lousy for FireTV)
- Itself DLNA server (okay, 7.2.10 7.2.8 instead on the 325v2 - you realize rapid product maintenance is different ..)
- Processing the plate rails acts cheaper, while still 325v5 damped rubber mountings, now yellow, for screwless plastic.
- Newer surface. While the more colorful, now need to be made settings partly in old, partly in new, partly in the additional programs. A place would have been better.
+ 2 Gigabit LAN sockets.
- Disconnections when I run it in pairing mode, without it seems to run so far ...

Why did I actually bought this thing? Because the price. I used to be with other Zyxel products satisfied (router). Meanwhile, I think it was the last Zyxel device which I bought.