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nph

macrumors 65816
Original poster
Feb 9, 2005
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I have an iMac 2011, and besides the HD being full so I need an external anyway I also wants to speed it up.
Would it be faster if I boot it from a Thunderbolt drive with SSD?
Or would the internal one still be faster?
 
I have an iMac 2011, and besides the HD being full so I need an external anyway I also wants to speed it up.
Would it be faster if I boot it from a Thunderbolt drive with SSD?
Or would the internal one still be faster?

An external SSD would be MUCH faster than the internal HDD. A HDD can only provide about 200 or so IOPS (I/O operations per second). By contrast... an SSD is about 100 times as fast... and probably delivers at least 20,000 IOPS.

Despite what gets reported... IOPS are what makes the computer fast (at least for client machines like your iMac). Bandwidth (in MB/s) is almost totally irrelevant. Unfortunately, we (as consumers) do not have good tools to objectively measure IOPS... so we typically retreat to the old HDD bandwidth style of measuring performance.

SSDs can provide similar performance irrespective if they are internal on the SATA port... or if external on a Thunderbolt port.

/Jim
 
Just to expand on what Jim said, an SSD is substantially faster than the internal hard disk even when plugged into a FW800 port. That's how I ran my 2009 27" i7 iMac from the day I got it, since I was moving from a Mac Pro 1,1 with an SSD for the OS and couldn't imagine going back to booting from a hard disk.
 
Just to expand on what Jim said, an SSD is substantially faster than the internal hard disk even when plugged into a FW800 port. That's how I ran my 2009 27" i7 iMac from the day I got it, since I was moving from a Mac Pro 1,1 with an SSD for the OS and couldn't imagine going back to booting from a hard disk.

I'll second that. I ran my 2010 iMac off of a FW800 SSD and daily operation of that computer was not noticeably different than my 2012 Fusion iMac.
 
Just to expand on what Jim said, an SSD is substantially faster than the internal hard disk even when plugged into a FW800 port. That's how I ran my 2009 27" i7 iMac from the day I got it, since I was moving from a Mac Pro 1,1 with an SSD for the OS and couldn't imagine going back to booting from a hard disk.
Actually it depends on the hard drive and controller in the Mac. On the newer iMacs, I am seeing data transfer that is faster than FW800. Although it depends on what you are doing with your system - SSDs are better at random access than HDs.

As for Thunderbolt, yes it usually be faster than an internal HD. You just need a good thunderbolt drive case and a good SSD to go in it.
 
Actually it depends on the hard drive and controller in the Mac. On the newer iMacs, I am seeing data transfer that is faster than FW800. Although it depends on what you are doing with your system - SSDs are better at random access than HDs.

As for Thunderbolt, yes it usually be faster than an internal HD. You just need a good thunderbolt drive case and a good SSD to go in it.

Actually, this illustrates the point - a fast internal hard drive may have a higher peak data transfer rate, but for the OS, random access (or, as Jim said, IOPs) is the key metric. Data transfer only really comes into play with large files (movies, large ZIP/DMG files, etc); for everything else, the ability of the SSD to read data from several locations concurrently will make the machine feel much faster, even when plugged into something like FW800.
 
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