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iMac hard drive upgrade

I'm assuming you currently have an HDD only unit. The specs for your unit, that are listed in MacTracker.app (available from the App Store) indicate 1 - 6.0 Gbps Serial ATA (SATA), 1 - 8.0 GT/s PCIe x4 which looks like it has a SATA interface for the HDD and a PCIe interface for an SSD. You might want to look at iFixit for more info, although I'm not sure the link below is for your specific model:

HDD: https://www.ifixit.com/Guide/iMac+Intel+27-Inch+Retina+5K+Display+Hard+Drive+Replacement/30522
SSD: https://www.ifixit.com/Guide/iMac+Intel+27-Inch+Retina+5K+Display+SSD+Replacement/30537

Those may not be for your specific model so you would need to verify it, but it states it's for a 27" iMac w/5K retina.

Personally if it was me I'd be looking at getting a Thunderbolt enclosure/cable and put an SSD in that without opening the unit up. That wouldn't be as fast as a PCIe SSD, but it would still be in the vicinity performance wise. You could then couple it with the internal drive to make a Fusion, or you could use the internal drive as a Time Machine backup for the external SSD. The reason I'm saying that is because with your unit being so new I'm assuming it's under warranty and opening the unit up will void the warranty. Of course, just because I'm assuming your unit is under warranty doesn't mean it is.

Hope this was helpful.
 
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Thanks for your tip I will check it out the Imac is brand new just a few weeks old
 
The thunderbolt port on a new unit is theoretically as fast as something connected directly to the unit. If USB 3.0 is really as fast as it claims even that would be fast enough to not slow down an SSD.

However, wouldn't it be nice if there was a little panel on the back that you could remove to get direct access to the drive?
 
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OldGuyTom said:
The thunderbolt port on a new unit is theoretically as fast as something connected directly to the unit. If USB 3.0 is really as fast as it claims even that would be fast enough to not slow down an SSD.

However, wouldn't it be nice if there was a little panel on the back that you could remove to get direct access to the drive?
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USB 3 isn't quite as fast as Thunderbolt, but USB 3 stuff is all over the place and the prices are much lower. If the device in a Thunderbolt enclosure is using PCI Express it will be faster than USB 3. However, both are so fast I don't know how many people would notice a difference.
 
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ZVH said:
USB 3 isn't quite as fast as Thunderbolt, but USB 3 stuff is all over the place and the prices are much lower. If the device in a Thunderbolt enclosure is using PCI Express it will be faster than USB 3. However, both are so fast I don't know how many people would notice a difference.
Click to expand...

PCI express SSDs internally connected make a SATA SSD seem slow as molasses.
 
MacRobert10 said:
....thought I would add that external thunderbolt is PCI express.
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Comparison of Thunderbolt vs. USB 3 can be found in the following article:

http://www.macworld.com/article/2039427/how-fast-is-usb-3-0-really-.html

When connected to a hard drive, USB 3.0 outperforms Thunderbolt. When connected to an SSD, Thunderbolt out performs USB 3.0, but not by that much (see the tables in the article).

My conclusion is that for a traditional backup drive, which is likely to be USB 3.0 anyway, there's no point in putting out the extra money for Thunderbolt. You actually get worse performance for top dollar.

The real question comes with an SSD. For example the bottom table in the article and following tests shows the SSD in Thunderbolt faster, but is it really fast enough to warrant the extra cost? A typical user isn't going to be performing all that many large file transfers (like 10GB at a time) and an SSD would typically be running in what I'd call a "burst" mode, meaning it accesses the drive in short bursts to acquire or write data. In such a mode, I'd have to wonder if anyone could noticeably detect a performance difference.
 
ZVH said:
Comparison of Thunderbolt vs. USB 3 can be found in the following article:

http://www.macworld.com/article/2039427/how-fast-is-usb-3-0-really-.html

When connected to a hard drive, USB 3.0 outperforms Thunderbolt. When connected to an SSD, Thunderbolt out performs USB 3.0, but not by that much (see the tables in the article).

My conclusion is that for a traditional backup drive, which is likely to be USB 3.0 anyway, there's no point in putting out the extra money for Thunderbolt. You actually get worse performance for top dollar.

The real question comes with an SSD. For example the bottom table in the article and following tests shows the SSD in Thunderbolt faster, but is it really fast enough to warrant the extra cost? A typical user isn't going to be performing all that many large file transfers (like 10GB at a time) and an SSD would typically be running in what I'd call a "burst" mode, meaning it accesses the drive in short bursts to acquire or write data. In such a mode, I'd have to wonder if anyone could noticeably detect a performance difference.
Click to expand...

SSDs earn their keep in faster boot speeds and faster initial application loading. Once everything's running and loaded, unless for some reason you're hitting the disk hard a lot, my experience is that you won't see much difference between an SSD and an HDD, especially if it's one of the newer, faster HDDs. I can see how someone using one of those old 5400 RPM spinners with lower areal density may see a drastic improvement when switching from HDD to SSD but with new high speed drives it's not that big a deal. I've swapped out my SSD with one of the high speed Hitachi HDD's and although the performance difference between the SSD and HDD can clearly be seen at boot up, it's barely noticeable when actually using the system.
 
OldGuyTom said:
The thunderbolt port on a new unit is theoretically as fast as something connected directly to the unit. If USB 3.0 is really as fast as it claims even that would be fast enough to not slow down an SSD.
Click to expand...

Thunderbolt and USB are all over the place. Speeds are dependent on the quality of the enclosure. Some Thunderbolt enclosures don't hit 300MB/sec write speed. The Inateck USB enclosure I use gets just under 400MB/sec write and just over 420MB/sec read speeds consistently.
 
...not to mention the fact that Thunderbolt enclosures typically cost a fortune and aren't that easy to come by.
 
Any recommendations for a low cost Thunderbolt enclosure to house a 2.5" SSD, or am I just dreaming again?
 
OldGuyTom said:
Any recommendations for a low cost Thunderbolt enclosure to house a 2.5" SSD, or am I just dreaming again?
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The Transcend StoreJet 500 is the least expensive TB enclosure I have found. It is very slow, at what is essentially SATA II speeds (~290MB/sec Write). I don't think the enclosure is meant to be opened.
http://www.amazon.com/Optimized-Inateck-External-Enclosure-Tool-free/dp/B00FCLG65U
USB 3 is much faster at ~400MB/sec Write and less than $20. I use Inateck.
 
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An Akitio TB2 enclosure ($200) with a Lycom card ($20) will allow you to use a PCIE SSD at nearly same speed as internal. You lose about 10% to TB2 overhead.

Or you clear the dining room table, put a blanket on it and get out some lights and tools.
 
bent christian said:
The Transcend StoreJet 500 is the least expensive TB enclosure I have found. It is very slow, at what is essentially SATA II speeds (~290MB/sec Write). I don't think the enclosure is meant to be opened.
USB 3 is much faster at ~400MB/sec Write and less than $20. I use Inateck.
Click to expand...

I have tried several USB 3 external box with SSD inside connected on the USBports on my Imac 5K and its not faster than the internal HDD
 
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FabLn said:
I have tried several USB 3 external box with SSD inside connected on the USBports on my Imac 5K and its not faster than the internal HDD
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That's surprising to me. I would check and make sure the USB enclosures are really running at full USB speed. Apparently some vendors are selling USB 2.0 items as 3.0 claiming "compatibility" because USB 2.0 is compatible with USB 3.0. A dirty trick for sure.
 
fcgerlach said:
Depends on What you consider "low cost". I'm using the Delock 42510 which can be found tor $85 (thunderbolt cable not included) from http://www.synchrotech.com/products...sd-drive-external-enclosure-delock-42510.html

Obviously you have to add the SSD which does bring the cost above most usb3 solutions, but it's still cheaper than other TB options I've seen.
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There is very little to gain to gain with this enclosure as a boot drive except TRIM. The necessity of TRIM is debatable for quality SSDs. An enclosure that utilizes UASP can hit top SATA III speeds, it doesn't need an external power supply, can be had for less than $20, and usually come with its own cable.
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FabLn said:
I have tried several USB 3 external box with SSD inside connected on the USBports on my Imac 5K and its not faster than the internal HDD
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Try an enclosure that uses USB Attached SCSI Protocol (UASP). You need this to achieve top SATA III speeds. Not all USB 3 enclosures are the same. Many are designed for 2.5" 5400RPM drives that max out below 80MB/sec.
 
It's very likely some low cost USB 3.0 vendors modify the direct USB 3.0 interface directly for compatibility without changing the actual drive interface, hence essentially bottlenecking the USB 3.0 output.
 
In the original thread the OP was looking into a "dual drive" offered by WD that had an SSD combined with an HDD. This unit was apparently discontinued just about the time the original thread was posted. Interestingly, I recently found out that WD has purchased SanDisk (one of the better know SSD manufacturers) which to me implies that the "dual drive" WD offered may not be some type of obscure discontinued drive, but maybe the wave of the future for very large storage. This may allow them to combine a decent sized SSD (like 128GB) with a large HDD (terabytes) at a reasonable price.
 
bent christian said:
Try an enclosure that uses USB Attached SCSI Protocol (UASP). You need this to achieve top SATA III speeds. Not all USB 3 enclosures are the same. Many are designed for 2.5" 5400RPM drives that max out below 80MB/sec.
Click to expand...

Some other points:

  • The SAT interface requires the SAT drivers. I'm not sure this is "allowed" using El Capitan.
  • I discovered that the internal SATA interface on some enclosures may be SATA 1 even though the USB interface may be USB 3.
Just some points to consider in addition to other comments offered up.
 
ZVH said:
Some other points:

  • The SAT interface requires the SAT drivers. I'm not sure this is "allowed" using El Capitan.
  • I discovered that the internal SATA interface on some enclosures may be SATA 1 even though the USB interface may be USB 3.
Just some points to consider in addition to other comments offered up.
Click to expand...

From what I've read the SAT drivers don't (or didn't) work with El Capitan. Whether this is a rootless problem or not I don't know. A decent third party enclosure may have drivers that support it under El Capitan but anyone should check with the manufacturer first.
 
BradHatter said:
From what I've read the SAT drivers don't (or didn't) work with El Capitan. Whether this is a rootless problem or not I don't know. A decent third party enclosure may have drivers that support it under El Capitan but anyone should check with the manufacturer first.
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If you look at some of the GitHub notes, that project hasn't been updated in almost a year. This project is open source, so the writer has every right to work on it (or not) when he sees fit. Link:

https://github.com/kasbert/OS-X-SAT-SMART-Driver
 
The SAT interface only really adds SMART monitoring support for external drives. Most decent enclosures will come with software that can provide the same support, and it won't be open source. I don't have anything against open source, but it has to be taken for what it is, and to me in most cases that means it's a hobby project. I've been stung by open source on Linux before. In one case the developer writing support for a graphics card just stopped doing it, and in another case a guy entered a project, messed up the code, published it, and then left. Companies have to stand behind their work.
 
OldGuyTom said:
The SAT interface only really adds SMART monitoring support for external drives. Most decent enclosures will come with software that can provide the same support, and it won't be open source. I don't have anything against open source, but it has to be taken for what it is, and to me in most cases that means it's a hobby project. I've been stung by open source on Linux before. In one case the developer writing support for a graphics card just stopped doing it, and in another case a guy entered a project, messed up the code, published it, and then left. Companies have to stand behind their work.
Click to expand...

There are rumors floating around that external SMART support will be implemented in the next OS X version. A lot of people don't want to install manufacturers drivers to their systems because often, especially after upgrades, they can have problems.
 
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