Upgraded Mac Mini powerful enough for Photoshop & downloading large image files?

Started Aug 7, 2013 | Discussions thread
Mateo Miller
Regular MemberPosts: 435Gear list
I'm not sure I agree
In reply to Basalite, Aug 10, 2013

From DigLloyd article on Fusion Drives

Mac Performance Guide: Fusion migration

"The question is, does Fusion actually migrate “frequently used” files to the SSD? All my testing suggesed that the answer ws “no”; it turns out that a special procedure is needed to actually make a Fusion volume, not just something that looks like a Fusion volume.

UPDATE: Fusion will NOT work unless the most current Disk Utility is used from a new version of the system. OWC has a tutorial for making a system that can use the proper version of Disk Utility.

In general, read speeds are far more important that write speeds. With some obvious exceptions, most all files are written once and read over and over. So the key questions are:

  • Do frequently used files stick to the SSD?
  • Do frequently used files on the hard drive get moved to the SSD?

Testing to try to force migration (repeated reads of the same files, repeated real world batch processing of image files, etc) did not result in any migration of those files even after many reads and even after giving the system hours to think about it.

It is possible that under some circumstances migration happens (this cannot be ruled out from my testing). But since the real-world scenarios I tested (the actual work I tend to do!) did not cause this benefit to accrue, it is eminently reasonable to conclude that counting on Fusion for performance gains is a misplaced idea.

Fusion maintains a 4GB buffer on the SSD. This buffer is used to soak up any disk writes that occur; if too many writes (4GB or more) occur in a short time, this buffer overflows and writes are then forced to the hard drive. An example of this might be downloading 5GB of image files, a large video file, etc.

All observations point to a very simple approach: writes initially go to the 4GB buffer. To maintain that 4GB buffer space, some items are “pushed down” to the hard drive. That is all.

As far as my testing shows, no actual migration back to the SSD occurs. This has implications for photographers working with Lightroom, Photoshop, etc: the key files that could benefit from speed might be pushed down to the hard drive, and stay there."

Basalite wrote:

Guaranteed speed for critical tasks: First off, lets dismiss this "guaranteed speed" speed nonsense for even with an SSD there is no guarantee of any particular speed.

I don't think he is "guaranteeing any particular speed"

What should matter with the Fusion Drive is real life performance and real life performance shows commonly accessed files reside on the SSD of the Fusion Drive, as expected.

His analysis differs from yours

I have yet to run into any of my image files, for example, that I have been working on recently that was then being accessed on the hard drive side of my Fusion Drive. How can I tell? Many of my images files are around 120-180MB in size. I can easily tell.

I'm not sure how one can tell where a file resides just because of its size. In addition the "Fusion Drive" presents itself as one drive which would also make it difficult to discern whether the file is residing on the SSD or the HD, but I'm prepared to be wrong.

Separate Boot drive: I know of no reason why you couldn't use another drive to boot from with a Fusion Drive equipped Mac. None at all.

Internal clone and Internal Time Machine: Beats the heck out of me what he is referring to except that maybe somehow he is expecting the drives to function as separate drives when the Fusion Drive is obviously not designed for that.

Upgradeable SSD: He says no but yet the Fusion Drive equipped Mac minis, for example, use a standard 2.5" SSD that can be easily swapped. In fact, there are people out there that have installed 256GB SSDs in their 2012 Mac minis and Disk Utility automatically created a Fusion Drive for them with the xisting 1TB HD.

I believe the new Disc Utility now allows the changing of SSD's as his update suggests.

The iMacs use a blade type SSD which presents a bigger challenge but aftermarket sources such as OWC have provided higher capacity SSDs of that style for the MacBook Air.

Upgradeable HDD: He says no but its no more difficult than simply swapping out the same HD in his preferred configuration and letting Disk Utility recreate the Fusion Drive. Plenty of people have already done this.

Works with disk repair tools: He says "Maybe, maybe not (according to Apple)" and yet dismisses the very good one that already comes with all Macs, Disk Utility. It's also odd to note something like this assuming that third party developers will not be presenting their own tools. It's a fleeting argument, at best.

Reliability: Already addressed in my previous post.

Serviceable by user: He says "Considerable “nerd” skill required to deal with Fusion volume setup (if failure)" Nonsense. Disk Utility does it automatically.

Can be partitioned: He says only "one partition, Fusion benefits are lost on the 2nd partition." That is incorrect or otherwise you wouldn't be able to run Windows in Boot Camp. It has also been shown that an SSD previously configured with a partition, for say Windows, prior to creating a Fusion drive will retain that partition and it will take advantage of the SSD speed since that it is residing on the SSD. What about a Mac that already has a factory Fusion Drive already installed and configured? Easy, you can unfuse the Fusion Drive and do the above. Both operations can be done in minutes in Terminal.

Special Disk Utility needed?: He says "YES (“earlier versions cannot be used”)" I say so? It comes with the Mac.

Already addressed above

Extra disk activity and thus increased noise and power consumption?: He says "YES— when files are moved around in the background," I say so? Fusion Drives are only equipped in desktop Macs which have no "power consumption" restrictions such as a laptop. You are also benefiting from the automated functionality of the Fusion Drive which is the whole point.

Sometimes things done "automatically" do not provide optimum results. Things like "auto exposure" can be accurate the majority of the time, but sometimes one wonders what the metering system was measuring when a horrible exposure occurs.

I think what DigLloyd is suggesting is that...

1. The Fusion Drive does not migrate data as advertised, at least with the testing he has done.

2. That with a minimal of fuss an alternative file management system can be used that utilizes SSD and increases the reliability of ones computer system. For some people that is important.

Noise? It's remarks like that that to me show a bias for his preferred configuration. The fact is, the Mac mini and iMac hard drives are essentially silent and have been for some time now.

LLoyd Chambers is a noted software engineer with an excellent reputation for testing and reviewing photographic, and computer equipment.

It seems to me that through out your response a tone of condescension and dismissiveness is used that is unwarranted.

Lloyd could be wrong, or things may have changed since his initial testing and review.

I personally decided to use an internal SSD for the OS and Apps and an external HD drive for my photos and data.  Whether my configuration is optimal for speed is "debatable" (I guess), but I know "exactly" where my photos are.  And they aren't migrating around from one drive to another without my knowledge or approval.

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