2020 iMac: 5500 XT vs. 5700 Pro vs. 5700 XT

[mj_]

First world problem: I need to spend some more money this year on hardware, and am thus going to replace my 2017 iMac with a brand-new 2020 iMac. Since my job consists of running multiple x86 VMs simultaneously to run x86 applications natively therein as well as running various x86-only Docker containers I absolutely need an Intel Mac on my desk for several years to come. After rebates and tax deductions the difference seems to be as follows:

6-core 5300M --> 8-core 5500 XT = +$210
8-core 5500 XT --> 8-core 5700 Pro = +$180
8-core 5700 Pro --> 8-core 5700 XT = +$170

RAM (8 GB) and SSD (512 GB) are identical between all of them, and I am going to upgrade RAM to 32 or even 64 GB myself.

Here's what I'm thinking, and please correct me if I'm wrong or missing something. In terms of performance I would most likely be fine with the 6-core 5300M for many years to come. Truth be told my current 2017 quad-core Core i5 is more than powerful enough for my current workflow. Thus, going from a 4-core to a 6-core will provide me with a nice performance boost already. However, adding an extra two cores will give me even more headroom for the future, and since this is going to be my final Intel-based Mac I would like to extend its life as long as it makes financial sense.

Graphics performance, on the other hand, is a bit trickier. While I don't really need it for my job I do enjoy playing a game or two every now and then in the evenings when the kids are in bed. I would thus not mind some additional graphics oomph but find it hard to justfiy it as business expense. Plus, and that's much more relevant, quiet operation is of utmost importance to me. I cannot stress this enough - I would sacrifice performance over noise any time. I do realize that the 5700 XT in particular is quite a bit faster than the 5500 XT but I fear that adding extra graphics oomph is going to make the rans run faster and thus louder during the day, and I would much prefer to sacrifice graphics performance for a more quiet daytime experience.

I am thus leaning towards the 8-core with Radeon 5500 XT GPU as sort of a compromise between noise and power. Does that make sense or am I missing something?

 

[velocityg4]

Since you need x86 still and want to game some. Plus have it last as long as possible. I'd go with the 5700 XT.

None of the gaming options are particularly mind blowing. But the GPU will definitely be the first to go obsolete with new games. So, the 5700 XT will give you the most headroom.

Of course since your work is running VMs and x86 code. You could always just jump ship now and build a gaming PC to also use for work. I can't imagine that requirement will change in five years. Unless you get a new job.

I don't really think there's a huge difference in running a modern macOS or Windows anymore. I've got both. Only a slight preference for macOS. But I think that's mostly due to nostalgia.

 

[wilberforce]

The 8-core i7 is an excellent CPU. The 10-core i9 has very little advantage, not worth it, and actually throttles in some situations.

The 5500XT is a good GPU. This is what I have. I recommend this over the 5300.

If you want the best GPU for games go all the way to the 5700XT, which is much faster. Do not bother with the in-between 5700.

I don't think you need to worry about fans. Both CPU and GPU clock down when not used.

I strongly recommend 1TB SSD. Remember, bigger SSDs are also faster, and you never want to fill more than 90% (been there, done that: slows down dramatically.)

The options that I think are very good value for their cost are:
1TB SSD
8-core i7 CPU
5500XT GPU
5700XT GPU (if you need/want it)

Other options are not so good value (IMO, as long term 27" iMac owner, and having heavily researched and compared them)

hope this helps

 

[ADGrant]

I have the 10 core i9. I run VMs and Docker containers too and you can never have too many cores or RAM. I also have the 5700XT too because I agree that the GPU is likely seem obsolete much sooner than the CPU.

Fan noise is not really an issue unless I am doing a couple of Docker builds while firing up a JetBrains IDE or two.

 

[mj_]

I should have added that since I need to spend the money in December (aka my credit card needs to be charged no later than Dec 31) I can't freely and individually configure an iMac the way I want it. Instead, I have to go with what is currently in stock either new or refurbished, and the choice I have is between an 8-core with 5300M and 1 TB SSD or an 8-core with 5500 XT / 5700 Pro / 5700 XT with 512 GB SSD. The latter should be plenty though as I already haven an external 1 TB SSD that I will simply keep connected to the iMac for stuff like VMs.

I've applied the SMC hack to my 2017 to lower fan speeds even below the stock 1,200 rpm since the fans were too loud for me even at that low speed. They are now running at ~900rpm and are virtually silent. Does anyone know whether that's still possible with the 2020 iMacs or am I going to be stuck with 1,200 rpm idle fans?

 

[wilberforce]

I've applied the SMC hack to my 2017 to lower fan speeds even below the stock 1,200 rpm since the fans were too loud for me even at that low speed. They are now running at ~900rpm and are virtually silent. Does anyone know whether that's still possible with the 2020 iMacs or am I going to be stuck with 1,200 rpm idle fans?

What exactly is the SMC hack?
Suggest explain how to do it, and someone may give it a try for you.

 

[CWallace]

In the Wikipedia entry on the family, all of the iMac AMD GPUs have the same TDP rating, with the higher-core models running at a lower clockspeed to keep the thermals in line. So you may not see much of a difference in heat between a 550XT and 5700XT.

I also replaced my 2017 (i7/580) with a 2020 model and the refurb I went with was an i7 / 5700 because they did not have an i7 / 5500XT with a 1TB SSD. My fans do spin up to a noticeable level when I play Valheim, but otherwise tend to stay in the 1200-1500RPM stage.

 

[mj_]

The "SMC hack" is basically a trick where you use one piece of software (smcFanControl) to modify a value in your iMac's SMC that defines the lowest possible fan speed, and then use another piece of software (MacsFanControl) to allow the fan to run at less than Apple's default 1,200rpm. In my case it throttles down to around 900 rpm, which makes a very noticeable (to me) difference.

Either way, I have already found an answer to this question, thanks to @franzb (see here for details). It is still possible albeit a bit finicky with the 2020 generation.

 

[mj_]

I've ordered the 8-core, 5500 XT, 512 GB SSD SKU today and am going to test it thoroughly. If the fan revs up even once during my 14-day return window while I'm working or if I can hear it even once without actively listening for it it's going back and I will have to figure out something else.

 

[wilberforce]

I've ordered the 8-core, 5500 XT, 512 GB SSD SKU today and am going to test it thoroughly. If the fan revs up even once during my 14-day return window while I'm working or if I can hear it even once without actively listening for it it's going back and I will have to figure out something else.

This is the machine that I have, and I am pretty happy with it and the fan noise. However, I do have a bit of background white noise (a water fountain outside) that drowns out the idle fan noise.
"If the fan revs up even once" might be a pretty high bar you are setting though. My fan will go up if I max out CPU or GPU. For example, if I run Cinebench the fan will start increasing after about 15 seconds and reach full speed (2700 rpm) after about a minute.
In "normal" use (whatever that means), the fan is permanently at idle (with very occasional exceptions)

 

[mj_]

"If the fan revs up even once" might be a pretty high bar you are setting though.

That's why I added "while I'm working". I don't mind it spinning up when I'm actually stressing the system. That's fine and expected behavior. However, if I'm sitting there concentrating and collaborating with a colleague on a large Excel spreadsheet talking on Teams and all of a sudden the fan revs up that would be an absolute deal-breaker. Over almost four years of daily use this hasn't happened once on my 2017, and I expect any future computer of mine to be as quiet as the current. If it isn't it's the wrong computer. I will give the 2020 a thorough test and see if it holds up to my expectations.

 

[wilberforce]

That's why I added "while I'm working". I don't mind it spinning up when I'm actually stressing the system. That's fine and expected behavior. However, if I'm sitting there concentrating and collaborating with a colleague on a large Excel spreadsheet talking on Teams and all of a sudden the fan revs up that would be an absolute deal-breaker. Over almost four years of daily use this hasn't happened once on my 2017, and I expect any future computer of mine to be as quiet as the current. If it isn't it's the wrong computer. I will give the 2020 a thorough test and see if it holds up to my expectations.

You should be good. I frequently do that sort of thing over Teams. In the last year (hundreds of Teams mtgs) I have once had fans spin up while Teams started stuttering and lagging, but I blamed that on a Teams glitch.

 

[mj_]

So the iMac arrived yesterday, and I couldn't believe how loud it is. This thing is a jet fan compared to the 2017, unbelievable. I was able to transfer my files and apply the SMC hack to lower revs to acceptable noise levels but had to go lower on the 2020 than the 2017 for it to become inaudible: 1,000 rpm on the 2017 vs. 850 rpm on the 2020. This morning I've had a one hour long Teams conference call with screen sharing and the fan did not rev up once. Looking good at first glance I'd say, let's see what the next two weeks will bring.

 

[wilberforce]

I think part of the reason new ones are noisier than old ones is that the vent screens at bottom aren't clogged up by dust yet, so have higher air flow = more noise. I don't believe there is any physical difference in the fan.
Wait a year or so for it to clog up with dust and it will be quieter. Problem is, the fan will then spin up sooner, because clogged.
(My experience comparing 2014 with 2020 iMac)

 

[mj_]

The iMac has passed its stress test. This morning, I had a 1.5 hour Teams conference with 8 simultaneous video feeds and a screen presentation, and while the CPU got too warm for my 900 rpm setting the fan remained at idle speeds alternating between 900 and 1,200 rpm throughout the entire meeting with temperatures never exceeding 65 °C. Under normal working conditions I have the fan running at 900 rpm with CPU temperatures hovering at around 45 °C, which is basically identical to my 2017.

The iMac can stay. The 2017 has moved on and become my wife's new primary work computer. I would like to take this opportunity and thank everybody for their input as it has been very insightful.