I wonder if the Blue series was originally just 5400 rpm and then they added 7200 rpms later on
Previous SATA generations of WD's Blue included a mix of 5,400 and 7,200 drives, all 3.5".
The current series appears to be all 2.5" and 5,400.
Just to add some interest into the mix, they've also released
a series of Blue SSHD's (presumably 5,400) as well.
Failure rates of new HDD's being very hard to come by, I use the
returns rates from a Euro etailer to get a baseline, the latest conclusion page gives a neat graph that covers late 2008 almost to date:
Conclusion - Les taux de retour des composants (14) - HardWare.fr Note that the black line (disques dur = hard drives) has been in consistent decline since ~late 2010 (P5 published 25 Octobre 2011) to date = HDD returns have been dropping for years, at least within the standard retail 1-year warranty period.
Note for comparison the SSD curve there, esp. the big spike which was almost entirely down to bad OCZ SSDs.
The latest main HDD page is:
Disques durs - Les taux de retour des composants (14) - HardWare.fr Obviously, if you don't read French well, use you favourite online translator to help out
EDIT: Just came acroos a post from ~ 9 months ago, detailing the switchover in the WD Blue range:
http://www.eteknix.com/western-digital-drops-green-drives-favor-blue/
Even with Green drives gone, WD still has a decent number of different colors. There is the Black which is aimed at enthusiasts, the standard consumer Blue, the NAS centered Red and the surveillance oriented Purple. The biggest difference between the Green and Blue drives was the slower spindle speed of the former. While the Blue advertised 7200rpm, the Greens had a range between 5400rpm and 7200rpm but really stuck to about 5600rpm most of the time. The biggest selling points of the Green drives were the reduced power consumption and price compared to the Blue. Of course, this came with a performance penalty due to the slower spindle speed.
