I have a 2011 iMac, quad i7 with 8Gb RAM and the stock HDD. I have trouble with my harddrive being excessively slow, and I am not sure if there's something wrong with it, or if it is the system. I have checked Apples call back for certain 2011 iMac HDDs, and mine is not one of them, based on the serial number. When my iMac has been asleep, and I wake it up. The machine is *extremely* slow whenever it needs harddrive access (Open/saving files, open/closing programs, accessing Spotlight, etc.), and this can go on for up to 30 minutes (!), and usually takes at least 10 minutes. Even opening a tab in Safari can take ~5 seconds, and entering a website adress and clicking enter, can lead to a ~5 second wait until it finally registers and starts loading the site. Starting a new application can take up to 5 minutes. Spotlight is practically unuseable as nothing loads. While it is going on, I can clearly hear the HDD working (No clicking, just the usual noisy I-am-working HDD sound), so I am certain that the drive is the cause. When it is done doing whatever it needs to do, the noise stops, and my computer becomes 'fast' again, ie. things open in a couple of bounces, Spotlight is instantaneous, etc. The situation is the same, albeit takes even longer, if I do a fresh boot of the computer, as it also has to load everything from the start that was open before. I have tried to do my own damage control and see if it Dropbox, in which I have 35Gb files and would be a likely culprit, but that does not appear to be the case. Otherwise I am pretty clueless as to what can be the cause. I usually have 100+ Gb space available on the HDD, and around 2Gb free RAM (Mavericks). Also, programs that are loaded into RAM, are usually quite responsive (Apart from when they access the HDD; as described with Safari and Spotlight above). Are there any programs that let me check what is writing/reading from the harddrive? Activity Monitor is not very helpful in this aspect, and in most cases the read/write activity is quite low when this is going on, which is puzzling. I am starting to think that my HDD is failing. I will be upgrading to an SSD when the next generation is announced, but I would still prefer not to have a failing HDD of course.