A disaster, a recovery and experiences with an iMac 5K Retina 3.4GHz

The inevitable finally happened a couple of weeks ago. Everything has an expiration date written on it – from humans over animals to the stuff we make. That certainly goes for computers. We (should) all know that and back up our data on a regular basis – preferably daily and even more often. But sometimes a break-down will come so unexpected and hit you so fast, you’ll be gasping for air and you’ll realise you weren’t all that well prepared after all.

That’s what happened to me on that wretched August 20, when my iMac mid-2011 started playing up as if it had been infected with a virus at 11.00am and stopped starting up altogether at 11.30am. I proclaimed it dead ten minutes later. It was a catastrophic event, not so much because of a lack of backups – I had made a full one only hours before – but because, at first, I thought it was a virus infection. That made me lose precious time running the anti-virus app I had on that machine. By the time ClamXAV had finished its scan and reported the system was clean, the iMac was already dying by the look of its flickering screen and its random response to my keyboard commands. And so, it went from working fine to a total loss in half an hour.

I had a really fresh backup of all my data, so what was there to worry about? For starters, I found myself without my main working tool in a matter of minutes. To make matters worse, I was on a deadline, so I didn’t have much time to think about my options.

The options

The least expensive option would have been to either quickly buy a Mac Mini or build a PC myself. The latter was ruled out because it would mean a significant investment in both money and time to get back to speed. It would be cheaper to buy a PC, but I would have to buy fresh copies of all the software I need. And despite having started playing (and building my own) with PCs back in the DOS ages, I would have to learn to work with Windows all over again as well. I would also be facing more security risks and have fewer skills to fix the system when something goes wrong.

On the other hand, a Mac Mini – even the “fastest” one – is much too slow for what I use it for. It would have meant saying goodbye to at least two magazines I currently writing for. There was no alternative to buying a new iMac – and a 21” wasn’t going to cut it, either. I realised that, in order to test video and compositing applications in a useful way, I really needed a 27” machine.

I decided I needed at least the 5K Retina 3.4GHz model, which was going to cost me €2100. However, I was in luck as this specific model was available until the next day only at €1900. To pay for the machine, I had to spend almost my entire savings for my yearly health insurance, which is a bit scary at my age and my health condition, but it was one or the other. So, the next day, I went out and bought my new iMac 5K Retina i5/3.4GHz with 4GB of VRAM, 8GB of RAM and a 1TB Fusion disk.

Recovering from disaster

Apple’s 8GB of RAM is hardly enough to type without stuttering, so I bought another 32GB of RAM from Crucial. Crucial is a high-quality memory vendor. They’re owned by Micron Technologies and their (no longer in business) “sibling brand” used to be Lexar which, in my opinion, was by far the better camera media brand.

Once I was settled with the hardware, I ran into all kinds of other problems. When my old iMac died, it took with it a lot of licences I should have been able to deactivate before I could even think of reinstalling them on another system. Alas, I spent the last 30 minutes of the old boy’s life running an anti-virus scanner. All those licences were lost. It took me a week before I got most of them back by courtesy of software developers whose apps I had reviewed before.

Some of them weren’t that generous, though, and I lost all of these forever.

Lesson one: Don’t just rely on backups. Once you start seeing your computer behave really strangely, deactivate your most important software, just in case. Then, and only then, run a fixing app or a virus scanner. Hooking up your old system disk to your new machine will most probably not work because most activations associate your Mac’s serial number with the app’s registration number. Only when you’re in a lot of luck might you be able to deactivate all apps from that old disk by starting up from your new machine.

I had backups of all my data, including movies copied to M-Discs and thousands of pictures backed up across half a dozen hard disk drives and Blue-Ray discs. It took me a week to find all those disks and optical media back and restore the lot.

Lesson two: Do keep backups in remote locations, but also do yourself a favour and spend enough time on actually keeping the local backups in a place where you’ll easily find everything back when disaster strikes.

Finally, don’t be surprised to find you’ve not yet (re)covered everything after three weeks time. If you have had a system for seven years – that’s 7 years – like I have, you will have a lot of valuable data literally lying around, but also a lot of rubbish that seemed like valuable at the time but really isn’t anymore by today’s standards.

Was it the right purchase for the job?

In my case, buying the iMac 5K Retina 3.4GHz was a no-brainer as I didn’t really have any money to spend on a new machine, let alone on a more expensive model. Nevertheless, even I was wondering from day one if I’d better purchased the top of the range. After all, the top 27” iMac has a faster, more powerful processor, is upgradeable to an even more powerful processor, and has a more powerful GPU with twice as much VRAM on board.

To put my mind at rest, I decided to do what I do best, which is test my new iMac’s performance under strenuous conditions. I ran tests with Apple’s Motion, Final Cut Pro X, Logic Pro X, Skylum’s Luminar 2018, Affinity Photo and Designer, and yet other apps.

I first ran Blackmagic Design’s Speed Test and was surprised the CPU is fast enough to handle 10-bit 4K video. But there’s video and video. So, I loaded Motion and ran three layers with Yanobox Nodes 2 and some other replicators and generators in 4K. The GPU held up very nicely until I combined the maximum resolution with the motion blur algorithm in Nodes 2 set to maximum. That slowed down the processing to a very low speed — more or less what I would have expected from my old iMac.

However, in Final Cut Pro X, the system never slowed down, not even when I combined a 10-minute 4K/60fps clip with the ColorSynth colour grading plug-in, a load of title effects and the TrackX plug-in by CoreMelt. It was only when I rendered the lot that it took some time – about 6 minutes for this particular clip – and it took 24 minutes to export the rendered clip to HEVC.265 via Compressor.

All things considered, the machine held up very well in all my tests and if you’re a Youtuber or even shooting short documentaries – say 10 minutes to half an hour – for publishing on Vimeo, for example, you’d benefit from a faster CPU and GPU as a matter of course, but the question is whether the price premium would be justified.

The extra memory I had installed made a huge difference. For example, I tested the memory performance by opening several images with Luminar 2018. This app sets aside memory for every image you open in a new window. With half a dozen images opened simultaneously, Luminar took up about 24GB of RAM from a total of 40GB I now have installed in the iMac. That means I still have plenty of memory to do other things without having to worry about memory swapping – which is the surefire way to slow down a Mac.


So, based on my experiences and tests run on this new iMac, I’d say – in most cases – you can do with a slower CPU as long as you have plenty of RAM installed to avoid bottlenecks in the processing pipeline.

It only becomes a real problem when you’re doing heavy stuff like rendering long movie clips with lots of effects or some other CPU- or GPU-intensive tasks. If that’s what you do daily, you would instinctively buy the fastest and most powerful iMac you can afford.

However, you can enjoy much faster GPU performance on my model iMac as well. Blackmagic Design has an external GPU that connects to the Mac via one of its two Thunderbolt 3 ports. The eGPU is a box with a ventilator and one of the fastest GPUs available inside. The only bottleneck you’ll then encounter will be the CPU’s performance – still, it will be faster.

In short, the iMac 3.4GHz does well for most people and for a lot of professionals who won’t use it for very CPU/GPU intensive tasks. And with plenty of memory inside, it’s quite a fast machine.