Semi related to this, I bought 6 identical Dell Optiplex 990 PCs from a former employer about 18 months ago. They were all Intel I7-2600k CPUs with 16GB DDR3 RAM and WD Blue 1TB HDDs. I have had 4 of the 6 machines die from HDD failures in the last month. I have already got replacement drives on standby for when the remaining 2 machines fail. The odd thing is that the disk failures all coincided with re-boots after installing Windows 7 updates!