ReadyNas Ultra Six Plus

Both have dual-core CPUs, but the one in the Ultra 6 Plus (RNDP600U-200) is much faster. The CPU in the Pro 6 (RNDP6000-200 aka RNDP600v2) is faster still.

See CPU Specs of the ReadyNAS

You can see the performance differences reflected in the performance numbers. See http://www.readynas.com/?page_id=3962#Performance and http://www.readynas.com/?page_id=5410

If you want maximum performance, get the Pro 6.

Aside from the increased performance via the CPU of the Pro6 (didn't realise they had launched that range!) what does the Pro6 offer over the Ultra 6 Plus?

Compared with the Ultra 6/Ultra 6 Plus, The Pro 6 also offers a 5 year warranty (3 years on Ultra 6/Ultra 6 Plus) and business features (such as NIC Teaming to bond the ethernet NICs together for failover/performance benefits; Rsync over SSH; Snapshot feature etc.). You may not need the business features, but the extra warranty in my opinion justifies getting the Pro 6 ignoring the other features. If you want to transcode (convert on the fly) HD 1080p video to stream to a mobile device such as the iPad, then currently out of the desktop ReadyNAS models only the Pro 6 is fast enough to do so. Take a look at http://www.readynas.com/plex



I should add that whether you'll notice a performance difference between the different models depends on a variety of factors, such as:

1. Will you be using multiple client machines to connect to the NAS at once?
2. Do you intend to run add-ons on the NAS (e.g. ReadyNAS Photos II, Torrent add-on, AirVideo, Plex etc.)?
3. What's the hardware like in your client machines? Do you use a single mechanical hard drive, a Solid State Drive, RAID with multiple mechanical hard drives?
4. Would you like to get a NAS that you can't take full advantage of yet, but will be able to as you move to a new computer or add better hardware (e.g. a SSD) to your existing one?

There's a good guide to performance expectations here: http://home.bott.ca/webserver/?p=363

If you're using a single mechanical hard drive in a single client machine and using the NAS simply as a basic file server you shouldn't notice much (if any) of a difference between the models in day-to-day usage.

I will most likely use the on the fly conversion properties but mostly it will be used by a couple of client machines which are present are stuck with standard sata drives. In the long term I will upgrade to SSD. I will be using the NAS for a very large number of files and at least two add-ons. It seems the Pro6 for warranty and performance is the better choice. Unless of course they release another even faster model by the time I get round to upgrading!