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macrumors newbie
Original poster
Jan 16, 2020
I want to replace the internal disk with an SSD on my iMac (20 inch, early 2009).
The current disk is an Hitachi with only 319gb using the SATA protocol.

I am looking at several SSD disks around 1TB but there seems to be several SATA variants. Would they all be compatible?

Any advice will be appreciated


macrumors 65816
Apr 30, 2008
USA (Virginia)
I think this page shows the specs for your model iMac:

A link on that page goes to:

which says:

... Early 2009 ... Aluminum iMac models -- all Aluminum iMacs with a 20-Inch or 24-Inch display -- each have a 3 Gb/s SATA connector for a 3.5" hard drive..."

That particular SATA connector is also called SATA 2 and is limited to about 300MB/second. Virtually anything sold now with a SATA interface will be SATA 3 (6 Gb/second, 600MB/second). The good news is that a SATA 3 device will work fine with your computer (although it will be limited to SATA 2 speeds). SATA 3 is also written as SATA III -- they are the same thing.

More about SATA:

Upgrading to an SSD will certainly increase performance of your system noticably. However, be aware that you might not get the read/write speeds advertised by the SSD manufacturer because you will be limited to the 300MB/second of your iMac's interface. So paying more money for speeds over 300MB won't be worth it (at least while the SSD is used withinin the iMac).

A number of years ago I put an SSD into my Early 2008 iMac, with excellent results. It's not easy, in my opinion, but it is feasible. Good luck!


macrumors 6502
May 19, 2019
Generally I see the old 20-inch machines as too old to really use in 2020 -- I get there are a lot of people that would disagree with me on that. But installing an SSD in your machine isn't that hard to do, and as Brian has stated above, you won't get the full potential out of the SSD you decide to use.

SATA SSD is what you are looking for. Tools you would need to disassemble your iMac to upgrade the storage would include:

Suction cup
T8 Torx screwdriver
T6 Torx screwdriver
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