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Just put a SSD in my imac optical drive bay - it looks slow?

Romf

Romf

macrumors 6502
Original poster
Jun 11, 2011
265
87
Paris, France
Hi,

My imac late-2009 (core 2duo) HDD failed, so I decided to change it for a new one, and to change the optical drive which I never use for a small SSD for the system.

First things first, everything seems to work fine - I made a clean install of Mavericks on the SSD, and the imac now boots up much faster than before (about as fast as my MBA). So I was thinking that everything's good.

But then I checked SSD speedtest results on the internet and it looks like I'm quite far from it:
On the SSD, I get results that are around:

Write: 138MB/s
Read: 268MB/s

Internet results are generally far from that. Also, on the HDD in the main HDD bay, i get 154/179 write/read MB/s...

If I verify the disk all is fine.
In the system report, under "SATA", for the SSD I see
Link Speed: 3 Gigabit
Negotiated Link Speed: 3 Gigabit
Physical Interconnect: SATA
which is same as the main HDD.
What shall I do?
 
Sorry, I forgot the main part :)

It's a Crucial M500 120Gb. Read that it works fine on an imac.
I activated TRIM
 
The screen you are looking for is in the drop down dialogue and should be the one in this image.:)
 

Attachments

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Thanks for your answer!

It seems I have some weird permission problems on the mac - just been on phone 1hour with Apple cos finder is crashing when just clicking on some files - could it be the reason?
Am trying on last thing they told me to solve it, and then will make a new clean install.


Anyway I couldnt make a bootable device with the firmware update for the ssd - tried this:
http://evan.borgstrom.ca/post/1314205955/osx-bootable-usb-from-iso
followed all steps on a firewire external HDD (as it says it wont work on a usb key) and when i boot holding shift, the external drive doesnt show up. Any idea?
 
Romf said:
Thanks for your answer!

It seems I have some weird permission problems on the mac - just been on phone 1hour with Apple cos finder is crashing when just clicking on some files - could it be the reason?
Am trying on last thing they told me to solve it, and then will make a new clean install.


Anyway I couldnt make a bootable device with the firmware update for the ssd - tried this:
http://evan.borgstrom.ca/post/1314205955/osx-bootable-usb-from-iso
followed all steps on a firewire external HDD (as it says it wont work on a usb key) and when i boot holding shift, the external drive doesnt show up. Any idea?
Click to expand...

I think if you are having other issues, it might new better to hold off until Apple are finished and you've done a clean install...Best to start off with a system that you know is working properly!:)
 
Did a clean install, all seems fine now.

Results are the same, see attached file :(

What's weird is that it seems fast (startup has never been so fast) but these are the results i get on a speedtest...
 

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What speed were you expecting? SATA 2 is 3 giga-BITS per second (Gb/s), which, when encoding is accounted for comes out to about 2.4 Gb/s (of actual data transfer), or 300 mega-BYTES (MB/s) per second.

So, accounting for other overhead, you are only 10% off the theoretical maximum speed of the link. Which is still pretty darn good.

Remember, in specs, b = bits; B = Bytes. A Byte is technically 8 bits, but with overhead and other functions of the interface, I usually just use a factor of 10 when converting. It's close enough for me.

:apple::apple:
 
viggen61 said:
What speed were you expecting? SATA 2 is 3 giga-BITS per second (Gb/s), which, when encoding is accounted for comes out to about 2.4 Gb/s (of actual data transfer), or 300 mega-BYTES (MB/s) per second.

So, accounting for other overhead, you are only 10% off the theoretical maximum speed of the link. Which is still pretty darn good.

Remember, in specs, b = bits; B = Bytes. A Byte is technically 8 bits, but with overhead and other functions of the interface, I usually just use a factor of 10 when converting. It's close enough for me.

:apple::apple:
Click to expand...
Thanks, so maybe all is is fine then - but is it normal that i get nearly same perfs with the physical HDD? Its weird because i can see the system is much faster than before with the ssd but with same perfs - so the gain would only be due to access times? :)
 
Romf said:
Thanks, so maybe all is is fine then - but is it normal that i get nearly same perfs with the physical HDD? Its weird because i can see the system is much faster than before with the ssd but with same perfs - so the gain would only be due to access times? :)
Click to expand...

You have a hard drive that gets 267MB/s on Black Magic? HDD are usually less than 120MB/s.

But that is just the sustained read speed for large file transfers (which is all that Black Magic measures). The real advantage of an SSD is the small file, random reads and writes. And that is where you see all the difference in the world with respect to boot times and application loads. Lots of small file transfers going on.

A HDD struggles with random RW because it has to swing the head around the platter. An SSD has more than 100 times the performance down in those ranges.

Your numbers look normal to me. I suspect the lower write speeds are due to the M500 architecture. Smaller capacity drives usually perform less than higher capacity since the high cap ones can use more channels in parallel.
 
Dadioh said:
You have a hard drive that gets 267MB/s on Black Magic? HDD are usually less than 120MB/s.

But that is just the sustained read speed for large file transfers (which is all that Black Magic measures). The real advantage of an SSD is the small file, random reads and writes. And that is where you see all the difference in the world with respect to boot times and application loads. Lots of small file transfers going on.

A HDD struggles with random RW because it has to swing the head around the platter. An SSD has more than 100 times the performance down in those ranges.

Your numbers look normal to me. I suspect the lower write speeds are due to the M500 architecture. Smaller capacity drives usually perform less than higher capacity since the high cap ones can use more channels in parallel.
Click to expand...

Nope, you are right: my hdd gets 154/179 which is less. Thanks for the help anyway, cant imagine how fast must be a system on one of these ssds that get 400-500mB :)
 
Romf said:
Nope, you are right: my hdd gets 154/179 which is less. Thanks for the help anyway, cant imagine how fast must be a system on one of these ssds that get 400-500mB :)
Click to expand...

Yeah PCI-E SSD are even faster, I get around 700 read/730 write. However it only shaves a second off from a traditional SSD, but I guess it's still faster :p.
 
Romf said:
Nope, you are right: my hdd gets 154/179 which is less. Thanks for the help anyway, cant imagine how fast must be a system on one of these ssds that get 400-500mB :)
Click to expand...

That is still a very fast hard drive. What model is it?

As far as comparing systems running SATA2 (like your 2009 iMac) and SATA3 the real world experience is not that different. For example I have an Intel 330 180GB SSD in my 2009 iMac 27" i7 SATA2 and a Vertex 4 128GB in my 2011 Mac Mini i5 SATA3. Although the Mac Mini blackmagic is something like 450-500MB/s and the iMac is only 240MB/s I seriously can't tell the difference in day to day operation. Sure the mini benchmarks faster and if I do a really BIG file transfer I might notice the difference in seconds, but that is such a rarity that I suspect you would be hard pressed to notice.

Again, it is the small file transfer rates that count in every day experience of how "Fast" an SSD feels.

IMHO anyways.
 
Lunfai said:
Yeah PCI-E SSD are even faster, I get around 700 read/730 write. However it only shaves a second off from a traditional SSD, but I guess it's still faster :p.
Click to expand...

What's the brand of the PCIe SSDs in the new iMacs ? Couldn't find anything related on the internet.
 
Dadioh said:
That is still a very fast hard drive. What model is it?

As far as comparing systems running SATA2 (like your 2009 iMac) and SATA3 the real world experience is not that different. For example I have an Intel 330 180GB SSD in my 2009 iMac 27" i7 SATA2 and a Vertex 4 128GB in my 2011 Mac Mini i5 SATA3. Although the Mac Mini blackmagic is something like 450-500MB/s and the iMac is only 240MB/s I seriously can't tell the difference in day to day operation. Sure the mini benchmarks faster and if I do a really BIG file transfer I might notice the difference in seconds, but that is such a rarity that I suspect you would be hard pressed to notice.

Again, it is the small file transfer rates that count in every day experience of how "Fast" an SSD feels.

IMHO anyways.
Click to expand...

The HDD is a 7200rpm Seagate (had to take the same brand to make it easy about fan speeds). I don't exactly know the model, had the job done by a serious shop as I was lazy to open the imac and do all the stuff :)
In disk utility it says: ST1000DM003-1CH162

Anyway, thanks for all informations - I'm new in the SSD adventure :)

Still, I couldn't move the Home folder to this HDD, had to let it on the SSD. Whenever I copy it to the HDD, then go in the advanced options of my acount to change the Home Folder, after restart all seems good (the home folder is really the new one on the HDD not the system SSD), but whenever I try to open some files (pics, PDF...) it crashes the finder as soon as I click on the file :(
Was on the phone with Apple for 1hour about it and they couldn't guess what to do - told me to make spotlight index again everything - which I did, then try clean install again - but still, won't work if I change the Home folder for the HDD (same folder works fine in its default location)
 
Further...

To the OP, those speeds are dead on for your system and capacity; the smaller the capacity the smaller the incompressible reads which is what you are testing with BlackMagic. It is dead on.

Regarding the NFGG and Apple PCIe testing, we have done quite a bit and I think this site allows us to link that in our info on the left.
 
Just so you don't feel too dissapointed, here's my results for a 21.5" 2010 iMac with a 120GB Corsair. While the numbers don't look great, the machine itself feels way faster with the SSD than it did with the HD.

DiskSpeedTest_zps91f33a9f.png
 
toddzrx said:
Just so you don't feel too dissapointed, here's my results for a 21.5" 2010 iMac with a 120GB Corsair. While the numbers don't look great, the machine itself feels way faster with the SSD than it did with the HD.

Image
Click to expand...

Thanks, but why the big difference? And your imac is more recent.
Anyway, as I said the imac feels much faster which is what's important, I was just asking in case something is wrong in my setup :)
 
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