Review Apple iMac 27-inch (2020) review

Aug 9, 2020
2
0
10
0
Recent high-end (non-pro) iMacs have been hobbled by crappy cooling. so why dance around the elephant in the room? What was the fan noise like during all the gaming and benchmarks you did to write the article?
 

varase

Estimable
Oct 29, 2016
25
0
4,580
0
Yeah, I ordered a core-i9 and a Radeon 5700 XT - is the chassis able to cool the combo under load?

-- Thanks, Verne
 
Aug 10, 2020
1
0
10
0
For me the problem screams NO!
I suppose you want to stay with a PCIe 3 logic board when read write speeds are already double what we see here in AMD motherboarded PCIe4 PCs? And Intel is soon to implement same, or even quadruple speeds with PCIe 5.0?

This is the Elephant in the Room for me, with there yet being nobody who has actually used one long enough to know. Read write speeds and the way CPU and GPU link to the motherboard is so much more sophisticated than what an iMac now has to offer, I put them in the same box as all those PC manufacturers passing off old kit at new kit prices in the hope customers do not know the difference......

That its performance outdoes the Mac Pro 7 and the iMac Pro in certain respects IF you shell out for the top BTO, may be a satisfying filip to help offset the debt involved in the total cost of ownership, but they are ALL running at half-speed, and you cant do anything to improve that, sorry.

I want an iMac that I control, not Apple. I want to fit ANY NVMe M.2. type SSD myself and be able to upgrade the graphics card and the processor even, and come Eternity when Apple have realised they can BigFoot it, I shall be able to do so.

There is nothing wrong with its look, and the thick black bezels stop you and your kids putting their greasy fingers on the screen. Why all you online pundits complain about the design that makes you always want to buy one, beats me!! Indeed I would go much further and go to a 30-40 inch square touchscreen. Why square? Because with squarescreens you do not have to rotate the screen to get a big enough vertical format image to look at and to edit, and Apples current Alu chinned screen is already getting back to square as it is. As a photographer the 16:9 formatted screen has limitations- except at 16:9. It means you get a much reduced image relative to what you want to be able to see.

So then all I have to do as designer is raise the base to be able to see at desk level properly without having to tilt the screen, and I do this by sticking all the components back in the base, where they used to be, remember? And where we can get at them. Have you ever stopped to realize the Fascistic Intent Apple have in preventing you doing more unless you pay Mac Pro prices, and even then....

By the way, the talk of pro microphones had me roaring with laughter, since they have to listen through solid walls of interference, electrical and physical, always have done!.
 

mprospero

Senior Editor
Oct 4, 2013
750
3
10,965
11
Recent high-end (non-pro) iMacs have been hobbled by crappy cooling. so why dance around the elephant in the room? What was the fan noise like during all the gaming and benchmarks you did to write the article?
The fan really kicked on during the Handbrake test, which was using just the CPU. I did hear the fan during the Final Cut Pro test, but it was much quieter.
 

varase

Estimable
Oct 29, 2016
25
0
4,580
0
Yeah, I ordered a core-i9 and a Radeon 5700 XT - is the chassis able to cool the combo under load?
Well, to answer my own question I've had no thermal issues.

My last primary was an iMac 5K purchased late in 2018 when my 2014 was going into the shop; this forced me to buy a 2017 - a year old model at this point - with a core-i7 4 core 8 thread, a Radeon Pro 580 8GB, and a 3 TB fusion drive. (I needed the capacity as the 2014 had a 3 TB fusion drive and in 2017 it was a 3 TB fusion drive or a 2 TB SSD which was uber expensive). The new model I really wanted arrived in early 2019 with a core-i9 and faster graphics.

The 2017's Kaby Lake processor was better than the 2014's Haswell processors and Radeon R9 M295X, but wasn't dramatically different.

This 2020 core-i9 10 core 20 thread 10910, Radeon Pro 5700 XT 16 GB with 40 compute units, 4 TB SSD, 10 gb ethernet, 8 GB -> 128 GB OWC memory machine is a beast.

My transcodes now take a third the time (just about exactly) and running my NNTP client fetching new headers, merging old headers, and grouping (about 72 million) messages now takes about 5 ½ minutes vs. almost an hour.

Also, now that my disk container is a single NVMe SSD I'm able to successfully use boot camp, whereas APFS on a 3 TB fusion drive was problematic and I really couldn't successfully create a non-problematic boot camp in Catalina (or I think Mojave).

I expect this to serve as my transition machine and will probably the the last and fastest consumer level Mac that's still boot campable, and I expect that any software which runs on Catalina will run on this machine while Apple silicon early adopters find and fix all of the transition problems for me.

Shadow of the Tomb Raider benchmarks on 1440p HDR with the highest settings on macOS at around 59 fps or so ... pretty much limited by the display refresh rate.

Also, found that transcoding a 1:58:58 1080p movie from MKV to an 8 bit HEVC mpeg4 took just around 14-18 minutes (depending on settings) at around 195-200 fps using Handbrake's H.265 (VideoToolBox), so it's able to use some seriously fast hardware transcode blocks somewhere (whether it's in the CPU, the T2 chip, or the GPU I have no idea).

In short, I'm very satisfied with this machine.
 
Aug 9, 2020
2
0
10
0
My transcodes now take a third the time (just about exactly) and running my NNTP client fetching new headers, merging old headers, and grouping (about 72 million) messages now takes about 5 ½ minutes vs. almost an hour.

Shadow of the Tomb Raider benchmarks on 1440p HDR with the highest settings on macOS at around 59 fps or so ... pretty much limited by the display refresh rate.

Also, found that transcoding a 1:58:58 1080p movie from MKV to an 8 bit HEVC mpeg4 took just around 14-18 minutes (depending on settings) at around 195-200 fps using Handbrake's H.265 (VideoToolBox), so it's able to use some seriously fast hardware transcode blocks somewhere (whether it's in the CPU, the T2 chip, or the GPU I have no idea).
It's great that you're not seeing any throttling in these tests and you're getting full value for the hardware. How is the noise level during transcodes, gaming, etc.?
 

varase

Estimable
Oct 29, 2016
25
0
4,580
0
Well, my transcode using H.265 (Video Toolbox) encoder (vt_h265 in HandBrake parlance) uses only around 25% of the CPU and takes 14-18 minutes, but flipping to HandBrake's x265 encoder put all the load on the CPU at which point the fan spun up nicely, CPU peaked, and the encode took an hour and a half. IIRC, the x264 encoder would take 15-20 minutes for the same transcode, but when I discovered the vt_h265 encoder I switched to HEVC for the smaller size and more rapid transcode.

I have TG Pro installed, but it simply pushes the fan to 100% more quickly, and at 100% the fan is noticeable but less so than my 16" MacBook Pro. It's got a deeper tone due to a larger diameter fan and sounds less like a gas station air pump with the release valve depressed.

I normally compute with a pair of Koss PortaPros on (in case I need to make a call or a call comes in on my iPhone) so I hardly notice the fan, and truth to tell I haven't even tried out the new variable EQ in the built-in speakers yet.

Nice things about the form factor staying the same is that I was able to take my 8 GB RAM configuration up to 128 GB using OWC RAM in less than a minute, and since everything is the same as my 2017 installing the 2020 5K was simply putting the 2017 into target disk mode, booting the 2020 and putting a Thunderbolt 3 cable between the two machines and letting Migration Assistant do it's thing. Then I put the 2020 where the 2017 used to sit and simply plugged in all the cables to connect all my peripherals. While I was at it I replaced a malfunctioning 7 port USB 3 hub with a new 10 port model which offers 5v 2.1A charging on every port (but no weird high voltage Qualcomm charging which can burn out the numerous peripherals that that charge on USB 3). Easy peasy.

I did have a major kerfuffle putting Boot Camp on though - I reformatted and restored from a Carbon Copy Cloner backup because of a glitch caused (I think) but not having boot security turned off.

In case you're interested, here's the glitch: once Boot Camp was installed, many times Disk Utility wouldn't successfully initialize, and my newly purchased Parallels 16 couldn't see the Boot Camp partition. When I found it was impossible to cleanly shut down the Mac I reformatted, reinstalled Catalina, and Migration Assistant restored from a CCC backup and the problem went away.

Trouble is, one of the reasons I got such a heavy configuration was my intention to have Boot Camp Win 10 so I could play all those AAA titles I had missed out on, and after everything was boringly working fine I tried again - with the same results.

I rebooted into Internet Recovery to check my disks and found the boot security settings, and first tried the trust Apple recognized OSes with the same result. I then set it to the allow me to boot anything setting and then everything started working fine: Parallels saw the Boot Camp disk, Disk Utility would initialize properly, and macOS would shut down cleanly.

Weird. I just installed the latest Windows 10 Pro 2004 on a 500 GB partition - you'd think that would be a recognized OS.

Anyway, after getting over that hurdle everything is going swimmingly. I've installed Steam and the big Halo bundle (Master Chief Collection?) and am waiting for my Xbox controller to arrive.

On the macOS side, Tomb Raider, Rise of the Tomb Raider, and Shadow of the Tomb Raider all seem to benchmark at around 59-60 FPS at high settings at 1440p HDR - HDR being a setting in SotTR - which enables the HDR stuff, but the display is really an EDR display since it technically can't hit the required 1000 NIT brightness (hats off to the Pro Display XDR).

So yeah, I'm very happy with this machine, and expect to use it for a few years. Who knows - maybe it'll even retain good resale value as the hottest consumer Mac ever with Boot Camp capability.

Edit: I didn't say there's no thermal throttling - I don't know how to objectively evaluate that. With all CPUs running hot, the primary cores are at around 100% and the secondary SMT cores appear to be around 30% according to the little iStat Menus histograms. Eventually under sustained load they lower to around 60% of speed, but at no time did I notice clocks dropping below the base clock of 3.6ghz.

The 10900K is the overclockable version and has a TDP of 125w but can use over 300w if adequately cooled (and they shaved the top of the chip to give you the surface area for that). This 10910 supposedly has a TDP of 95w but seems to be limited to 150w or so under load.

The iMac 5K is not cooled like a gaming PC so I have no idea what this chip could do with liquid metal heat transfer and a liquid cooling loop. It's a Mac which can game, not a Mac designed to game.
 
Last edited:

varase

Estimable
Oct 29, 2016
25
0
4,580
0
For me the problem screams NO!
I suppose you want to stay with a PCIe 3 logic board when read write speeds are already double what we see here in AMD motherboarded PCIe4 PCs? And Intel is soon to implement same, or even quadruple speeds with PCIe 5.0?

This is the Elephant in the Room for me, with there yet being nobody who has actually used one long enough to know. Read write speeds and the way CPU and GPU link to the motherboard is so much more sophisticated than what an iMac now has to offer, I put them in the same box as all those PC manufacturers passing off old kit at new kit prices in the hope customers do not know the difference......

That its performance outdoes the Mac Pro 7 and the iMac Pro in certain respects IF you shell out for the top BTO, may be a satisfying filip to help offset the debt involved in the total cost of ownership, but they are ALL running at half-speed, and you cant do anything to improve that, sorry.

I want an iMac that I control, not Apple. I want to fit ANY NVMe M.2. type SSD myself and be able to upgrade the graphics card and the processor even, and come Eternity when Apple have realised they can BigFoot it, I shall be able to do so.

There is nothing wrong with its look, and the thick black bezels stop you and your kids putting their greasy fingers on the screen. Why all you online pundits complain about the design that makes you always want to buy one, beats me!! Indeed I would go much further and go to a 30-40 inch square touchscreen. Why square? Because with squarescreens you do not have to rotate the screen to get a big enough vertical format image to look at and to edit, and Apples current Alu chinned screen is already getting back to square as it is. As a photographer the 16:9 formatted screen has limitations- except at 16:9. It means you get a much reduced image relative to what you want to be able to see.

So then all I have to do as designer is raise the base to be able to see at desk level properly without having to tilt the screen, and I do this by sticking all the components back in the base, where they used to be, remember? And where we can get at them. Have you ever stopped to realize the Fascistic Intent Apple have in preventing you doing more unless you pay Mac Pro prices, and even then....

By the way, the talk of pro microphones had me roaring with laughter, since they have to listen through solid walls of interference, electrical and physical, always have done!.
You know, it's interesting to see those who push home-built component monstrosities because they never tell you the whole story - about how much time they spend debugging bleeding edge motherboards and PCI peripherals and what they had to do to get everything working together.

The real elephant in the room is what happens when things go wrong, and the application developer, the OS developer, and half a dozen hardware vendors are all pointing fingers at one another.

Sure you can upgrade and balance bits and pieces of your system, and you can hobble them together and get some kind of workflow going, but everything doesn't work right out-of-the-box and the tuning and support factors mean you're spending a lot more time debugging and trying to get things like colors balanced and true - let alone colors balanced between screens and say print devices.

And another thing: once you add in the cost of a high density display which can match the 5K iMac's 500 NIT EDR panel all your savings go out the window - if you can find one.

You mention TCO - but I don't think you know what you're talking about, or you're placing no value on your own time. TCO on an iMac is very good, because when you're ready to sell you're going to get substantially more back on your original investment than you would with a monster system with no single source of support. iMacs are actually very competitive on price (provided you don't buy Apple RAM).

If you buy 4 or 8 TB SSDs, they come on daughter cards so if you have a future storage problem or upgrade needs, there may be OEM vendors who offer replacements - and these PCIe SSDs are seriously fast.

Unless you're running a render farm - and that's not what these machines are designed to do - they have plenty of power for the intended purpose. and you can get better 24x7 domestic support from people who speak english you can understand, and domestic repair depots where you can get fixed price repairs if things go really south.
 
Thread starter Similar threads Forum Replies Date
admin Article Commentary 0
admin Article Commentary 0
admin Article Commentary 1
admin Article Commentary 1
admin Article Commentary 0
admin Article Commentary 0
admin Article Commentary 8
admin Article Commentary 0
admin Article Commentary 0
admin Article Commentary 0
admin Article Commentary 0
admin Article Commentary 0
admin Article Commentary 0
admin Article Commentary 0
admin Article Commentary 0
admin Article Commentary 0
admin Article Commentary 0
admin Article Commentary 0
admin Article Commentary 0
henrytcasey Article Commentary 0

ASK THE COMMUNITY