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I have an iMac 27 inch, and one summer the room temperature was up to 40C, and I came home that day, and the hard drive was really slow. I then rebooted the machine and it took something like 8 minutes to boot up since then.
So I suspect the hard drive is not working so well any more. Can I now use one of those Samsung T1 SSD USB drive, or a Seagate 2TB external USB drive, or a WD Thunderbolt My Book, and boot up the iMac using this drive from now on?
The thing is, how do I make such a bootable drive, when the original iMac isn't working so well? I do have a Mac Mini, a Macbook Air, and a Macbook Pro Retina, running Mavericks or Yosemite, so I do have some Macs to work with in order to set up this external hard drive.
(I supposed using the Samsung T1 would make the iMac really fast too? That's because I can connect the Samsung T1 to my Macbook Pro and copy files at a speed of 400MB/s)
P.S. and actually, since my Mac Mini (with USB 3.0) has an internal 5400rpm hard drive, can't I make such an external SSD boot up drive for the Mac Mini, and boot up my Mac Mini using this SSD from now on, and make the Mac Mini run a lot faster that way?