New SSD very slow

[DontDuckWithMe]

Hi,

Today I replaced the superdrive of my late 2009 iMac with a Samsung 850 Evo SSD thinking I could bring it back to life but I soon noticed that the speed is basically identical to that of the HDD.

Now, I know the connector is an old Sata II so I wasn't expecting crazy speeds, but 130 mb/s both write and read seems a little bit slow to me, considering I've also done a clean install of OS X...

There must be some kind of problem, right? I thought my mac could reach at least 230 mb/s with a decent SSD.

 

[kepler20b]

nah

Odds are that you are either bottlenecked by your RAM or CPU.

 

[DontDuckWithMe]

Could this be the problem or is it normal?

 

[matreya]

Image

Could this be the problem or is it normal?

Try swapping your SSD and HDD around and see if that improves the speed of the SSD.

 

[briand06]

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Could this be the problem or is it normal?

It might be. The speed of the mechanical HD of my 2008 iMac is twice than yours.

 

[kepler20b]

what is your random read/write speeds? 130mb/s read/write speeds are slow for an SSD but that only pertains to moving large files. Random read/write speeds essentially dictate everything else you need your HD for.

benchmark it and show us your random read/write.

 

[DontDuckWithMe]

benchmark it and show us your random read/write.

You mean this?

 

[phpmaven]

You mean this?

Image

If those are your SSD numbers, then something is wrong. You should be getting 3 or 4 times those numbers.

 

[Bruno09]

If those are your SSD numbers, then something is wrong. You should be getting 3 or 4 times those numbers.

3 or 4 times : no. This iMac has a SATA 2 interface.

For example on a Late 2009 Macbook (SATA 2 too) with a Crucial MX100 256 Go I get :

Write : 230 MB/s
Read : 260 MB/s

(for info : 400 and 490 MB/s on a Macbook Pro Early 2011 SATA 3, Crucial M500 480 Go)

 

[drambuie]

Follow matreya's advice, and swap the drives. It looks like the superdrive port is limited to negotiating at SATA 1 speeds. If the HDD port negotiates with the SSD at SATA 2 speeds, then the benchmark readings should be approximately double your present readings.

 

[DontDuckWithMe]

I don't know how safe it is to do something like this:

But it worked, I think

Of course, I'll buy some kind of proper adapter for the SSD

 

[Bruno09]

Much better

Double sided tape is fine for SSDs in iMacs.

 

[kepler20b]

safe imo.

I used velcro once in my PC.


Is the mac quicker now?

 

[phpmaven]

3 or 4 times : no. This iMac has a SATA 2 interface.

For example on a Late 2009 Macbook (SATA 2 too) with a Crucial MX100 256 Go I get :

Write : 230 MB/s
Read : 260 MB/s

(for info : 400 and 490 MB/s on a Macbook Pro Early 2011 SATA 3, Crucial M500 480 Go)

I stand corrected.