SSD speed in older iMac

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SSD speed in older iMac

I replaced my dead HDD in my 2013 iMac with a new 2TB SSD instead of the Fusion drive I had. Using BlackMagic disk speed test I am getting speeds of about 450 write and 500 read. My RAID drive is less than half that speed (remember when RAID was all about speed?!!). I see the new M1 MacBooks get write speeds about 1000 and read of 1300.

How is it that my new SSD (albeit in an older iMac) does not get speeds anything like the SSD in the new M1 MacBooks? Are my read and write speeds normal for an SSD in an older iMac, or should they be faster?

Thanks!

iMac Line (2012 and Later)

Posted on Nov 24, 2020 10:54 PM

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Answer 1

Nov 25, 2020 9:58 AM in response to Cartoonguy

There are two factors limiting the speed: the SATA bus, as already mentioned, and the USB3 bus.

It is as if your "Ferrari" SSD may be capable of reaching 300Km/h, but the speed limit on the highway is only 120Km/h.

I have a real world experience of that: my Crucial X8 SSD would reach about 500MBps on my 2014 MBP (USB3 bus).

It reaches over 920MBps on my 2019 16" MBP (because the USB-c "autobahn" allows for it 😎)

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Answer 2

Nov 25, 2020 8:52 AM in response to Cartoonguy

Yes, your speeds are normal because you were using a SATA SSD that is significantly slower than the M.2 SSDs that you will find in the newer MacBooks.

Hope this helps!

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Answer 3

Cartoonguy Author

Level 2

199 points

Nov 25, 2020 10:45 AM in response to Luis Sequeira1

Right, this is kind of what I was thinking might be the case, so thank you for confirming. Basically, it's not the SSD, but the fact that my older iMac has a slower transfer speed, so this is as fast as it will get, but still much faster than the HDD it replaced. Main thing was to make sure that all is good, which it is. Cheers.

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SSD speed in older iMac

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