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October 2012

Performance of 'Fusion' Drive (OWC Accelsior 480GB PCIe SSD + 2TB HDD)

After setting up the Fusion drive (480GB OWC Accelsior PCIe SSD + 2TB hard drive), I tested it by writing 256GB of files to it.

The OWC Accelsior PCIe SSD looks like an IDEAL choice for making a Fusion drive. It can be used in a Mac Pro PCIe slot, or with any Mac having Thunderbolt by installing it into a OWC Helios external case.

UPDATE: careful testing shows ZERO benefit either with the Accelsior PCIe SSD or with a SATA SSD (these are both non-Apple configs, no comment here on Apple’s official setup). All that is seen with non-Apple SSD+HDD fused drives so far is simple, dumb JBOD behavior: SSD fills up, overflows to hard drive, thereafter speeds are hard drive speeds, no migration of files occurs.

Testing was on a Mac Pro. Could it be that the feature has certain requirements?

  • Perhaps it has to be the latest chipset from Intel?
  • Perhaps the SSD has to be on a SATA III port (Mac Pro is only SATA II).
  • Is the version of 'diskutil' used different than that shipped with Fusion-enabled Macs? (the version from 10.8.2 was used for testing).

Researching— a 2012 MacMini will arrive tomorrow.

Read more.

Write speed with a PCIe SSD + hard drive fusion volume
Write speed with a PCIe SSD + hard drive fusion volume
Fusion volume speed — 256GB on 480GB SSD + 2TB hard drive
Fusion volume speed — 256GB on 480GB SSD + 2TB hard drive
Aura SSD for 2013 Mac Pro

Setting Up Your Own High Performance 'Fusion' Drive

Step by step how-to in setting up your own Apple Fusion drive., which is smart about locating frequently used portions of files on the fast SSD.

I used an OWC Mercury Accelsior 480GB PCIe SSD along with a 2TB hard drive for a 2.48TB logical volume.

The 'fused' volume below is really a 480GB PCIe SSD and a 2TB hard drive!

OWC Mercury Elite Pro port layout
Fusion volume

OWC Mercury Elite Pro 4TB External with USB 3, Firewire, eSATA Ports

Read the MacPerformanceGuide review of the 4TB OWC Mercury Elite Pro.

The OWC Mercury Elite Pro external hard drive has been updated to offer connectivity options that are ideal for all Mac users:

  • USB 3 port for high speed I/O on Macs with USB 3 (2012 MacMini, 2012 MacBook Pro, 2012 iMac).
  • eSATA port for high speed I/O on Mac Pro systems without USB 3 (Mac Pro will have USB 3 at some point).
  • Firewire 800/400 for backward compatibility with systems lacking either eSATA or USB 3.
  • USB 3 drops down to USB 2 on older Macs with only USB 2.
OWC Mercury Elite Pro port layout
OWC Mercury Elite Pro port layout
Which Mac? Memory and Storage? Backup Questions?
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Apple’s Fusion Drive

With the new MacMini and new iMac, Apple offers its new “Fusion” drive, which front-ends a hard drive with a 128GB SSD (probably 120GB in reality, given Apple’s checkered history in mis-stating capacity).

Write operations hit the SSD drive first and thus are relatively fast compard to the hard drive, and some files are also stored on the SSD for fast access (OS files, applications). In the background, files migrate to and fro.

Apple’s description suggests that the SSD uses MFU (most frequently used) or perhaps MRU (most recently used) to store useful stuff on the SSD. No doubt it will prove much more responsive than a hard drive alone, and in this sense it is a great technology for mainstream users.

Reliability concerns

Apple has published a knowledge base note: Mac mini (Late 2012) and iMac (Late 2012): About Fusion Drive, on which I comment here.

Presented as a single volume on your Mac, Fusion Drive automatically and dynamically moves frequently used files to Flash storage for quicker access, while infrequently used items move to the hard disk.

As a result you'll enjoy shorter startup times, and as the system learns how you work you'll see faster application launches and quicker file access. Fusion Drive manages all this automatically in the background.

Let it be clear that more complexity, especially with data storage, implicitly carries a negative implication in terms of reliability and bugs (unless one is talking about systems engineered for fault-tolerance).

It is for the reliability aspects that I would rather have one separate SSD and one separate hard drive on which I selectively store my data (e.g. system and apps and a few things like scratch and Lightroom catalogs and big working files on the SSD, photo files on the hard drive). In practice, this works great, though it does entail using one’s brains to a minor degree. Apple prefers to require zero brain power for users of its products, and that is an admirable goal.

Reliability: with the Fusion drive, if either drive goes south then the system dies. Two drives will be less reliable than one drive, end of story. That’s because the Fusion drive approach apparently is either/or: a file is either on the SSD or it’s on the hard drive; the SSD drive is not a write-through caching solution but a sort of extra-smart JBOD. A caching solution would have had fault-tolerant aspects and supported more than one hard drive, but that involves its own complexities also. Bottom line is that SSD prices are steadily dropping and that simpler is better (but at a higher price for a larger SSD, for those who want guaranteed faster performance without the complexity).

However, the target market involves a lot of customers who just store casual data (email, contacts, etc) and who are not too worred about a week’s downtime at the Apple Store to get a failure fixed. For that type of use, the Fusion drive sounds like a very useful technology. I am not one of those people, and I doubt that very many professionals are either. But for my family members who do basic stuff (email, web, calendar, etc), the Fusion drive drive sounds nifty, offering value in terms of low price an (promised) relatively high performance.


There are other implications however, as pointed out in the Apple tech note:

  • “ Earlier versions of Disk Utility can't be used with a Fusion Drive.”
  • Limit of one partition, and the Fusion drive functionality is not available for the 2nd partition.
  • Unclear whether one can swap in a larger or faster drive to replace the Apple OEM hard drive.
  • “Third party disk utilities may or may not work with a Fusion Drive”.
  • “ the system attempting to mount the Fusion Drive in Target Disk Mode must have OS X Mountain Lion version 10.8.2 or later”.
  • Etcetera

Probably not a big deal for casual users, but the point is, complexity breeds more complexity. I deem this a marginal solution for that reason.


Barring a bracket change, the prior MacMini and this new one can both take two internal drives. OWC offers both the bracket and drives.

A higher performance and simpler and more flexible solution for those seeking very high performance in a MacMini is a 480GB or 960GB SSD (single drive) with an optional 2nd SSD or hard drive (or two hard drives). A 480GB SSD is more expensive than Apple’s Fusion offering, but one 480GB SSD is likely beyond adequate for most users, and it is very, very fast (and simple).


Analysis of the new Mac Pro — Oops Nothing Announced

Which Apple product do media professionals need the most? The Mac Pro.

Which product is least important to Apple? The Mac Pro.

Yesterday, Apple pre-announced the new iMac, but it’s not due out for 6-8 weeks, some time in December. It can’t even be ordered yet.

So if a Mac Pro was due, say, in January, wouldn’t it also have been pre-announced? Apple apparently committed to a Mac Pro for 2013, but the lack of any Mac Pro announcement yesterday was conspicuous in its absence.

The silence doesn’t make me hold my breath for a January arrival, which even so would make it 2.5 years since the last real refresh (the no-op June 2012 “update” does not qualify).

Recent Mac Pro related articles.

Files and Folders That Are Invisible in Finder Windows (But Should Not Be)

I was working away yesterday in Terminal when I noticed several files and one large folders that I could see via 'ls' in Terminal, but which were not displayed in the Finder window.

Mind you, these are not “special” files; the were my own Stuff, hidden from me by the Finder for no reason at all (some kind of bug). The maddening thing was figuring out how to make them visible in the Finder window.

So here’s how to do it in Terminal— the details of using Terminal and a command line are complex (cannot teach it here), but you have to 'cd' to the correct directory, then (for example) in my case a folder called “WEB_SERVER_SETUP”, here is how to make it pop into view in the Finder window:

setfile -a v WEB_SERVER_SETUP

Note: you must have XCode installed (a developer tool) to have /usr/bin/setfile.

It is absurd that this should even be necessary. The idea of hiding files has always seemed like a really bad design decision to me. The Finder doesn’t even have a “show hidden files” option, which in my view is a data loss bug— I knew I had that folder around, but just couldn’t seem to find it (SpotLight found it for me)! It is easy enough to throw away an “empty” folder that is not empty.

Here is the command line help for 'setfile'. What it doesn’t tell you is that 'v' means “make it visible” and 'V' means “make it invisible”. And it should be 'setfile', not 'SetFile'. Buggy help.

Arne D writes that “chflags nohidden path” has the same effect as “setfile -a v path”.

Analysis of the Oct 2012 MacMini

With up to a 2.6 GHz quad-core CPU, the new MacMini is a winner for anyone who already has a screen and keyboard.

The MacMini can now be a hot little number!

  • Fast quad-core CPU up to 2.6 GHz (for only $899!).
  • Up to 16GB memory.
  • Up to two internal hard drives or SSDs (960GB X 2 SSD possible via OWC upgrade).
  • Four USB 3.0 ports. This is a critical improvement; it allows connecting high-speed peripherals, such as backup drives. USB 3.0 is especially valuable for hyper-fast SSD-based external drives, but also high capacity external hard drives.
  • One Thunderbolt port, handy for (for example) ultra high speed PCIe SSD support, such as the Mercury Helios, assuming it can be daisy-chained off a Thunderbolt display (unsure here).
  • Firewire 800 port — handy for compatibility.
  • SDXC card slot — easy download of digital camera image files.
  • Gigabit ethernet. Perfect for networking.

What’s missing?

The MacMini is cool. And disappointing: what would happen if it had four memory slots to make 32GB possible, one short PCIe slot and two Thunderbolt ports and four USB ports and a slightly faster CPU? It would be killer. And so what if it was twice its diminutive size? It would not be quite as chic, but would still be very small, and it would be a Mac Pro alternative for some users. Apple always seems to truncate Mac products short of greatness.

Could a MacMini tide you over until the next Mac Pro model?

Waiting for a new Mac Pro sometime next year? A quad-core 2.66 GHz MacMini with 16GB memory from OWC will cost you about $1014. The memory won’t move forward, but if you install a fast 6G SSD, that handily solves the disk I/O speed issue, and it and any USB 3 backup drives can move forward into a Mac Pro, as can a display.

To be clear, 16GB memory is way too limiting for my uses, but for many users it will do the job. And so the above might make sense for those on the fence waiting and currently without a Mac Pro.

On the other hand, Apple certified refurbished 2.8 GHz quad-core Mac Pros are about $1819, so maybe it’s really only a solution if the budget has to be kept in check. We’re talking ~$950 more to get a Mac Pro vs Mac Mini (I’m counting the cost of 16GB for the Mac Pro in there).

So maybe the MacMini is really the best value for those looking for tiny. Or for a file server or music server, etc.

Mark W writes:

I am currently running a Mac Mini server (the 2011 version with 16GB memory).

I had several thoughts:

- With the fast interfaces (i.e. USB 3.0 and Thunderbolt), I think there really an advantage to having ones drives external because of maintenance issues (i.e. one can replace/add/remove drives without having to do surgery on the system) without having to give up on the performance.

- I would rather use hardware RAID than software RAID - seems more reliable to me. I currently use the CalDigit drives and have found them to be reliable.

- The physical footprint of a Mac Mini and a RAID drive (such as the CalDigit VR2) is much smaller than a Mac Pro. Also the power consumption is lower (not a minor consideration as electricity is relatively expensive in the northeastern US).

- I put all user files on the external HW RAID drives and use the second internal drive as a Time Machine backup of the primary system drive. This allows me to rebuild the primary drive relatively quickly should it fail.

- I see the primary disadvantages being the limited memory capacity (16Gb) (as you mention) and potentially the inability to put higher performance video cards in the machine.

Thus, overall, I find the Mac Mini server to be very useful and well priced as a server. Reliability has been superb.

DIGLLOYD: Regarding drive failures, the high quality power supply and cooling system of a Mac Pro are unbeatable (and quiet). Adding/replacing a drive is not “surgery” but very fast and straightforward (not so for an iMac though). External drives are unlikely to have the same quality power supply or cooling system as the Mac Pro, so I’m not going to agree that external is better comparing a MacMini to Mac Pro. Also, the added noise of external drives is not a win, and cables cost money and can have problems too, be crimped, go bad, etc.

On the flip side, power consumption of a MacMini indeed a lot lower (though the gap closes considerably if one uses an external RAID). And it’s a lot smaller. It makes the most sense so long as one uses the internal drives and perhaps one external; once there are 2/3/4 drives, this becomes a mess, and I’d say a Mac Pro starts to look a lot more favorable.

Regarding reliability, I would expect the MacMini to be quite reliable, but it’s the hard drives that are the main concern in most systems.

The best choice comes down to what the machine will actually be used for; the Mac Pro wins hands down as a workstation that doubles as a server (far more expandable, far more top-end memory, PCIe cards, storage, etc), but is a very bulky box for, say, a home media server where one only needs less than 10TB storage. Given that a MacMini with 16GB is over $1000, a Mac Pro 2.8 GHz refurb for $2819 is not very far away and far more attractive if it is to be used as more than a headless server in a closet.

Aura SSD for 2013 Mac Pro

Analysis of the Oct 2012 iMac

Apple’s new (October 2012) iMac addresses key shortcomings of previous models, namely high speed disk I/O expansion:

  • Four USB 3.0 ports. This is a critical improvement; it allows connecting high-speed peripherals, such as backup drives. USB 3.0 is especially valuable for hyper-fast SSD-based external drives, but also high capacity external hard drives.
  • Dual Thunderbolt ports, handy for (for example) ultra high speed PCIe SSD support, such as the Mercury Helios.
  • Fast quad-core CPUs up to 3.2 GHz.
  • Improved display.

Other features are “interesting” but of lesser interest:

  • The hybrid (“Fusion”) dual-drive flash/hard drive approach increases complexity and would seem to lower reliability (failure of either either drive means downtime). Given past drive failures in iMacs and the difficulty of replacing a drive in an iMac, I recommend one large SSD and one large hard drive, each assigned to its own functionality. It’s unclear if one of each can be ordered.
  • 32GB max memory— just fine for most everyone, but not for me.
  • SDXC card slot (in awkward rear location!).

I’ll have more to say after further study, and the new models won’t actually arrive until December (“Coming in December” according to Apple).

21.5" model

The 21.5" iMac apparently has no user-upgradeable memory. This sets an appalling new low for form over function in an iMac. As per the Apple marketing page:

The 21.5-inch iMac comes with 8GB of memory and can be configured online with 16GB.

On the 27-inch iMac, 8GB of memory comes standard, and you can upgrade to 16GB or 32GB. Configure and buy your iMac at the Apple Online Store and it will arrive with the memory already installed. Or add more memory to the 27-inch model yourself by popping open the easy-to-access memory panel on the back

MacBook Pro 13" with Retina Display  — Analysis versus the 15" Model

The compact form factor of the 13" model is always attractive, especially since the latest model (Oct 2012) how has an 2560 X 1600 Retina display upgrade (but it’s optional and expensive and limits memory to 8GB).

For those who must have a smaller form factor, the 13" MacBook Pro appears to be quite a lovely little unit and for many uses, it will be a very fast and very enjoyable computer. Beautifully designed, and very fast for most uses.

But once spiffed up to the Retina display and fast CPU; the 13" Retina model offers poor value by comparison with the 15" Retina model, because the 13" MBP Retina is crippled in two key ways, and also has a smaller screen:

  • Dual-core CPU, meaning that Lightroom and Photoshop will never run anywhere near their possible speed. Converting my Nikon D800 files is already sluggish on my 2.7 GHz MBP Retina quad-core, I don’t see a dual-core CPU as a viable CPU for my non-casual use. A MacMini has a quad-core 2.6 GHz i7 CPU, what are they thinking here?
  • Perhaps even worse, the 13" MacBook Pro offers a maximum of 8GB of soldered-on non-upgradeable memory, which can be a serious hit to performance when working with larger files, far more performance degrading than dual vs quad core. This is a key distinction from the non-Retina 13" model, which accepts 16GB memory at low cost. Seriously, a MacMini can do 16GB, but not a top-flight 13" MBP? What are they thinking?
  • Smaller working screen area, very noticeable in practice. This is not a defining issue, but it is significant to working efficiently.

The 13" MacBook Pro with Retina display is stillborn as far as my workflow.

Spending $2699 for a crippled 13" MBP makes sense only if a slight savings in size and weight are the #1 priority (the price drops to $2199 if one opts for the 256GB flash drive, but that is not enough for me in the field).

When one adds in the cost of AppleCare, backup, peripherals, the total system cost looks even less favorable for the 13" Retina model. Everyone has their own needs and priorities, but for me the MBP 13" Retina looks like a very poor value by comparison with the 15" model. It becomes a luxury good, at which it succeeds admirably, but in terms of my needs for serious work, it is a design failure.

  MBP 13" Retina MBP 15" Retina
CPU up to 2.9 GHz dual core up to 2.7 GHz quad core
Memory 8GB max 8GB or 16GB
Flash drive up to 768GB up to 768GB
Screen resolution 2560 X 1600 2880 X 1920
Working area at Retina(best) resolution* 1280 X 800
(scaled up is less cramped)
1440 X 960
(scaled up is less cramped)
Graphics** Intel HD Graphics 4000 Intel HD Graphics 4000
NVIDIA GeForce GT 650M with
1GB of GDDR5 memory and automatic graphics switching
Weight 3.57 pounds 4.46 pounds
Dimensions 12.35 X 8.62 X 0.75 14.13 X 9.17 X 0.71
Price $2699
(2.9 GHz dual core, 8GB, 512GB)
$2199 for 256GB flash config
(2.6 GHz quad-core, 16GB, 512GB)

* Screen resolution should be confused with screen useable working space in conventional terms of how much can be displayed. Scaling up the screen helps.

** Mostly irrelevant. I have never measured any gains for “faster” graphics for anything I do and OpenGL causes glitches in Photoshop anyway, so I turn it off.

MacBook Pro Lineup: Will we ever see built-in Cell Support?

Apple is apparently all set to release a 13" MacBook Pro with Retina display. Good, surely, but perhaps nothing really new there.

But one thing lacking in all the MacBook Pro models (never seen yet) is built-in connectivity to the internet via a cell phone signal (e.g., AT&T or Verizon).

Why is it that I have to have a personal hot spot on my phone to enable my MBP to connect to the internet?

I want to wake up my laptop anywhere with a cell signal, and be on the internet, no phone involved. The iPad can use a cell phone signal for the internet, so why can’t the MacBook Pro do the same?

Built-in is not a problem

Having cell support built-in does constraing it to one carrier— but this is the reality for most users anyway; switching is expensive and typically reception is best with one carrier or another.

Still, suppose AT&T is built in and for travel one wants Verizon— so plug in an iPhone or hot spot that connects to Verizon.

OS X already lets the user select the network connection (USB, Bluetooth, ethernet, wireless, etc), so it is not an issue two have two services, one of which is built in (other than the egregious phone company pricing).

Better yet, if OS X could spread the bandwidth needs over more than one connection according to speed and or monthly usage limits, road warriors could have a speedier and potentially less costly solution than going “over” with one carrier.

Which Mac? Memory and Storage? Backup Questions?
✓ MPG consulting starts you out on solid footing.

MacBook Pro with Retina Display — Thoughts on the 13" Model

Rumors abound of the imminent release of a 13" MacBook Pro with Retina display (see my review of the 15" MacBook Pro with Retina display). We should know next week.

Like many, I confess to being attracted to the more compact form factor of the 13" model, especially if the display is the Retina display (should be 2560 X 1600 pixels in theory). On the other hand, my needs don’t involve airplane travel or similar, and so I’d take a 17" model (N/A) preferentially to a 15" or 13" model, just for the screen real estate (3840 X 2560 would be incredible!).

Today as I was processing some Nikon D800 files into 16-bit TIF, I noted that Photoshop CS6 was using all 4 CPU cores. Now realize that the speed of the 15" model is about as fast as any Mac today, and it is too slow.

In short, if the 13" MacBook Pro with Retina display offers 16GB memory and the same size SSD, etc, if it remains a dual-core system, it will inherently be crippled for my type of usage compared to a 15" model, and immediately disqualified as a machine for my usage, nor would I recommend it to any photographer working with D800 size files.

In short, if the 13" MBP Retina turns out to be a dual core CPU, then one should really only consider it if size and weight are the #1 consideration. Since the 15" model is already svelte, a dual-core 13" model does not sound attractive at all.

Upgrade Your Mac Memory
At much lower cost than Apple, with more options!

Apple 27" iMac Seagate 1TB Drive Replacement Program

All drives can fail of course, but some are more prone to it.

Swapping system and data is a daunting task for some users, and not too classy for Apple to punt on the hardest step.

You will need to have the original Mac OS installation discs that were shipped with your iMac in order to reinstall your operating system, other applications, and any backed up data after your hard drive is replaced.

I recommend cloning to an external drive (preferably two) instead— far faster and much lower risk of screwup. And Apple could have done this for users, which would have been a class act.

Mac Pro = value, iMac = storm cloud

As a professional, I use my computer every day (7 X 12 typically). The only sensible choice for a professional who depends on their gear is a Mac Pro.

An iMac is a disaster waiting to happen— if I want to upgrade the drive, or the drive dies, I cannot be down for 5-10 days waiting for Apple to fix it. Which means I would have to buy two of them, neither of which supports the memory I need, the extra drives I need or the PCIe cards I need. The iMac is a very poor medium and long investment for a professional. It is a poor value in this sense, even though it “costs less”.

With a Mac Pro, a bad drive is a 5 minute swap. Over and done with.


MacBook Pro with Retina Display — Thoughts from on the Road and at Home

Over the better part of the past decade I’ve used a MacBook Pro for traveling, especially to Yosemite or the White Mountains or Death Valley, and sometimes further, such as the Thelon Wilderness.

Most of those years, the MBP was simply a glorified download station, being useful for little else without internet connectivity, and slow enough that working with big files was not such a great experience.

But in recent years, the capability to use the internet via cell phone personal hot spot has been a godsend, even at 12,000' elevation in the White Mountains (though one needs just the right spot for it to work of course).

It just keeps getting better. Advances with the 2012 MacBook Pro with Retina display and recent models that matter to me on the road include the following:

  • USB3 port — WAY faster than Firewire 800— bus-powers a small backup drive, such as the OWC Mercury Elite Pro Mini (the USB3 with SSD model). This really saves me time in backup after some very long days.
  • 16GB memory — the old limit of 8GB really cramped my ability to do certain Photoshop things in the field, 16GB kills that limitation.
  • Retina display — the best display I’ve ever used or seen, at any price. Glare is still there, but it’s as good as any other model I’ve used., and it’s absolutely gorgeous.
  • Speed — the MBB with Retina display is as fast for opening my huge Nikon D800 files as my Mac Pro desktop.

What’s missing? A built-in cell connection so that I don’t need to bother with a phone to connect to the internet. And I wish it would not wake itself up on bumpy roads.

screen burn-in on MacBook Pro Retina display
Taking shelter at 12,000'
Sigma DP1 Merrill

Media integrity and performance verification— one of many reasons to use DiskTester

When a hard drive is shipped from the factory, the recording media is a blank slate with possible bad areas. It’s always a good idea to verify your new hard drive before putting it into “production use”.

Most bad areas can be mapped out, but this can result in oddball performance anomalies. While not a big deal for a single drive, it’s a glitch for a multi-drive RAID setup.

Verifying drives is especially good idea for RAID-0 striping, where one goofy drive can slow down the whole RAID. In my own testing, variations up to 12% in speed can be observed between identical model drives, with the “dogs” perhaps being future drives more likely to fail: buy 5 and use the fastest 4 for a 4-drive RAID. Test each drive individually for starters, then test as a RAID later.

For example, back in 2011 I cherry-picked 4 Hitachi 7K2000 drives for my main Mac Pro. I saw speeds from 118MB/sec to 133MB/sec. This four fastest drives yielded about 520MB/sec speed versus 480MB/sec for an average setup. Not a huge amount, but why not? The other drives became backups, and the one serious dud was returned.

How DiskTester helps

Filling a volume

DiskTester makes the testing and verification process easy with its fill-volume facility. By doing so, the drive is forced to detect and map out any bad blocks. In addition, DiskTester verifies all data during the read phase of fill-volume (which can be repeated so long as the created files remains on the disk).

The detailed results across the entire drive can be graphed to show any performance anomalies, stutter, etc. This is true for single drives and RAID.

Get DiskTester here.

Video capture

Video users in particular might want to verify that the drive or the RAID doesn’t have downward spikes in performance, so as to preclude lost frames.

Graphing the results

When DiskTester has finished filling the volume, you can paste the numbers into the supplied spreadsheet. This is a fantastic way to see just what your drive is doing.

In the graph below, the decline in speed across the drive is readily visible; this is normal for all hard drives (SSDs do not drop off this way). The spike for the last 1% of the drive should be ignored; this is not a drive issue but rather a Mac OS X file system behavior when the drive is almost full.

See Why You Need More Space Than You Need and Larger Hard Drives Are Faster Than Smaller Ones.

Graphed drive-speed data from DiskTester fill-volume
Graphed drive-speed data from DiskTester fill-volume
ThunderBay 4 - The Speed To Create. The Capacity To Dream.

How to Safely Transfer Data or Verify Backups

Suppose that you are switching to a new system, and you want to know that your key data is tranferred without damage (photos, videos, spreadsheets, documents, etc)?

Or that you want to be able to verify a backup long after it has been made, say next month or next year?

While infrequent, data corruption does happen, and I get related inquiries from time to time from unfortunate users. The more valuable your data, the more important it is to take steps to ensure that data rot or data corruption has not occurred. Causes can include bad media, bad cables, software bugs of various kinds, etc.

See How to Safely Transfer Data or Verify Backups.

IntegrityChecker verify command
IntegrityChecker after verifying files
Which Mac? Memory and Storage? Backup Questions?
✓ MPG consulting starts you out on solid footing.

16GB Memory for MacBook Pro — No-brainer at $120

I’ve used a MacBook Pro for many years now when traveling, my home-base machine being a Mac Pro.


Apple MacBook Pro 16GB memory price (2 X 8GB)
Apple MacBook Pro 16GB memory price (2 X 8GB)

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