I think with that setup you keep the speed but you lost the dual channel.
Do a Geekbench and you will see your performance dropped.
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Decision time i7 vs i9 for new 2020 iMac?
- Thread starter BasilFawlty
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I think with that setup you keep the speed but you lost the dual channel.
Do a Geekbench and you will see your performance dropped.
This is the latest rule of thumb from other people testing it. Your and 9to5mac's video config loses dual channel in which the benchmarks( mainly geekbench) show a greater drop in performance than the speed drop.
1. If putting 4 sticks of the same size in, put the matched pairs in the adjacent slots( ie 1 and 2 and 3 and 4).
2. if putting just 2 sticks in the machine, put in either slots 2 and 4 or 1 and 3.
3. Don’t mix different sizes of RAM. But if you must, keeping dual channel is better than restoring full speed. So put the same size sticks in 2 and 4 and the other size in 1 and 3.
Nobody is taking that single video as gospel, but as one among multiple reviews that show the same thing. There has been multiple videos from multiple reviewers. None of them have shown any significant difference between the i7 or the i9 so far. As I've already said multiple times, there MIGHT be a situation where the i9 is faster but so far there isn't much proof of this. There is two specific tests where the i9 is slightly faster - In Logic where it handled 6 tracks more than the i7, which is 4,8% and the Xcode test that they developed themselves, which was 5,2% faster on the i9. But at the same time in the Lightroom Classic test with 500 RAW photos the i7 was actually 20 seconds faster than the i9, even when the i7 was configured with a much lower GPU.
The problem with the few comparison tests that have been made so far, is that they usually don't spec the machine identical with only the CPU as a difference. In the Max Tech test the i7 had had only 32GB ram and a smaller GPU. Both machines used the 512 GB SSD which is known to be quite a bit slower than the 1+ TB options.
Your 22% can't really be used as a comparison to the i7 in the Max Tech video, since there is quite a difference between the 512 GB SSD and the 2 TB option you have. I don't know how much ram you have in your machine, but if you have more than 32 GB then that would also be a significant difference from the Max Tech video.
Then comes other factors such how the benchmark was run. Was it run on a machine that might have other things going on in the background or not, was it run back to back with other benchmarks or was it allowed to cool down between runs. Was it run more than once and then the average result taken or was it the best result that was chosen. True benchmarking is an art in itself and we're never going to see any YouTuber or Mac site buy 4+ almost identical iMacs to compare one component at a time. So what we can do is stop taking everything so personal in this discussion and try to help each other.
I should be receiving my i7/5700XT/1TB/10Gbit/64GB within a few days and if anybody has an i9/5700XT/1TB/32 or 64GB machine, we could do some direct comparisons in a bunch of different benchmarks and tests. We will have to agree on a specific way of testing to ensure the results are comparable. We could also get results from a config like yours with the 2TB option, but since it's at least one additional difference it will not be a true i7 vs i9 comparison.
I'd be happy to gather all the data and compile the overall results. This way we could hopefully get a fairly accurate view of the exact performance of each machine. But it will also require a decent amount of time and effort from the people participating.
Are you aware of any other reviews that actually test XCode build performance. I realize that my 22% performance is not a fair comparison with an i7 with only 512GB. It does however highlight that comparing build performance of an i7 vs an i9 using machines with only a 512GB isn’t that useful. I doubt i9s with 512GB will be a common configuration.
The Lightroom Classic test was interesting. Clearly it doesn’t use the GPU. It probably doesn’t make efficient use of the CPU either which would be typical for Adobe. I am guessing the performance in this test might be constrained by the SSD and there is some variation in the SSD performance on the two machines.
Well now I'm confused.
It almost seems like I should ditch the 8 GB of Apple RAM so I can keep dual channel and 2,666 MHz.
Agreed. Anecdotally, it appears that some benchmarks are bottlenecked by the 512GB SSD, just as others are bottlenecked by the T2 chip. I’m glad I bumped up to the 1TB now.
I could see people who connect to external thunderbolt or NAS storage buying the 512GB, which should be plenty for the OS and apps for a lot of people. I thought about doing that myself
Unfortunately, that's the case with these 2020 iMacs, unless you get more of the same Apple RAM and limit yourself to 16GB, or order a different amount of Apple RAM to begin with. It's a disheartening waste of money knowing what Apple charges for this stuff.
Yes, I have seen people talking about doing that. Not the best idea if you are looking to maximize performance and if you are not, why would you spend $400 or so on an i9 upgrade. My view is RAM first (self install), SSD second and only after those have been adequately addressed, upgrade the GPU and/or CPU (depending on what you plan to use the computer for).
1TB is the bare minimum SSD size for me so I upgraded to 2TB just to be sure. I would rather have too much than too little.
I did a bunch of tests and then realized I should have simply read the instructions that came with my TimeTec RAM!
But, yes, it's true that to get the best RAM performance, you need to use all the same kind of chips—either in all 4 slots, or in only 2. No configurations I tried with mixed chips could match the performance.
But I guess that's fine. Max Tech's tests showed diminishing returns with more than 32 GB of RAM, and almost no difference beyond 64 GB (in their tests). So I'm losing only 8 GB by removing the Apple chips and using only my two TimeTec chips. I think that's acceptable and I still get the best performance.
Sidenote: I had to go back to Geekbench 4 in order to get RAM performance data. Novabench reports it, too, but I got a little freaked out when Novabench asked for permission to monitor keystrokes in any program (WHAT?).
You truly need therapy, which of course you can afford.
BetterHelp – Online Counseling
Or if you want to save money for more Mac upgrades in the future you could just grow up, that’s free. 😘
You truly need to understand what getting a good laugh is like which of course is probably very difficult for you.
But here we are. 😂
Sorry you got suckered into overpaying for your RAM. But I guess you have all that extra cash from downgrading to your i7...
I can easily cancel my Amazon order from last night and reorder to save myself $100.00 so thanks for the advice! 😂
Bummer. It looks like HyperX is out of their 32 GB chips, which would have saved me about $25 each from the Timetec chips from Amazon.
While I like HyperX for desktop memory, I'd chose Crucial certified RAM over anything for the iMac.
I built a 10 core i9-10850k Hackintosh over the weekend.
XCode Benchmark result: 187.234s
CPU is running stock speeds.
64GB of 3600 MHz - Timing 18-22-22-42
2TB AData XPG SX8200 PRO
Large air cooled heatsink - peak temps in mid 80's during the build (C)
Not faster than @ADGrant's 178 second result (which I wonder if that is repeatable?), but substantially faster than the 217 seconds from the i9 in MaxTech's video.
XCode Benchmark result: 187.234s
CPU is running stock speeds.
64GB of 3600 MHz - Timing 18-22-22-42
2TB AData XPG SX8200 PRO
Large air cooled heatsink - peak temps in mid 80's during the build (C)
Not faster than @ADGrant's 178 second result (which I wonder if that is repeatable?), but substantially faster than the 217 seconds from the i9 in MaxTech's video.
What's that supposed to mean? You are coming off as unnecessarily arrogant and uninformed.
Crucial RAM is definitely solid. I bought the Samsung version which is fine as well.
OK, I'll take you at your word.
But I didn't recommend it to anyone here. I just happen to enjoy the process and also wanted to provide a reference point for the performance that the 10-core iMac is leaving on the table with its underpowered cooling system, etc.
Yeah maybe. Your’s can probably have a higher sustained clock speed if your cooling is adequate. But does it worth it ... I don’t think.
I’m so much looking forward to Apple to stop build macOS for x86 just to eradicate hackintosh for ever. I’m pretty much like Steve Jobs on this one.
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I have been thinking about why the performance of the I9 is somewhat higher than that of the I7 (!)
To start with, I’ve read all messages in this thread and many reviews (Yes, l’m waiting for my customized iMac to arrive). Next I studied the data sheets of Intel.
Conclusions:
- the processors are almost identical, they both dissipate 125 Watts
- the I7 runs max at 5.1 GHz, the I9 max 5.0 Ghz
- the I7 runs nominal at 3.8 GHz, the I9 nominal 3.6 Ghz.
Others have observed that, at full load (benchmarking), these CPUs start to throttle because the iMac cannot keep the temperature of the die (the chip) below 100 degrees Celsius. During this benchmarking the I7 cores manage to run at a higher speed than the (10) cores of the I9. With these (unrealistic)
circumstances I would expect slightly better scores for the I7. Because more cores causes somewhat more overhead. However, under stress the I9 scores about 10% better than the I7.
How come ? (according to me):
In digital electronics speed and dissipation are not lineair. Double clock speed (GHz) might require up to 4 times more power (Watts). Because the I9 runs 2 extra cores with a somewhat lower overall clock frequency than the I7, the I9 can execute more instructions per second (More efficient).
Next question: Why is the I9 somewhat faster in full load single core benchmarks?
The single I7 core should run at 5.1 GHz and the I9 at 5.0 GHz (source: Intel datasheets).
The only reason that I can think of, is the higher size of the L3 processor cache within the I9 (as suggested by someone else in this thread).
Finally my opinion on the question: ... should I buy the I7 or upgrade to an I9?
For the price/performance it‘s a nobrainer... don’t do it. The cpu performs up to about 10% faster. But the cpu only defines a part of the overall performance of the complete system (other parts are also important: GPU, memory, SSD, bus structure/speed etc.). So the overall system performance gain is likely to be limited to less than 5%.
But 10 cores sounds/feels good. And after a couple of years you might get a better price for your iMac. I also went for the full tuning for my Italian Giulia from 280 to 320 hp. It’s totally useless (100 km/h speed limit) , but I love it 😎.
Whatever configuration you choose, good luck and be happy with your new iMac 2020👌
To start with, I’ve read all messages in this thread and many reviews (Yes, l’m waiting for my customized iMac to arrive). Next I studied the data sheets of Intel.
Conclusions:
- the processors are almost identical, they both dissipate 125 Watts
- the I7 runs max at 5.1 GHz, the I9 max 5.0 Ghz
- the I7 runs nominal at 3.8 GHz, the I9 nominal 3.6 Ghz.
Others have observed that, at full load (benchmarking), these CPUs start to throttle because the iMac cannot keep the temperature of the die (the chip) below 100 degrees Celsius. During this benchmarking the I7 cores manage to run at a higher speed than the (10) cores of the I9. With these (unrealistic)
circumstances I would expect slightly better scores for the I7. Because more cores causes somewhat more overhead. However, under stress the I9 scores about 10% better than the I7.
How come ? (according to me):
In digital electronics speed and dissipation are not lineair. Double clock speed (GHz) might require up to 4 times more power (Watts). Because the I9 runs 2 extra cores with a somewhat lower overall clock frequency than the I7, the I9 can execute more instructions per second (More efficient).
Next question: Why is the I9 somewhat faster in full load single core benchmarks?
The single I7 core should run at 5.1 GHz and the I9 at 5.0 GHz (source: Intel datasheets).
The only reason that I can think of, is the higher size of the L3 processor cache within the I9 (as suggested by someone else in this thread).
Finally my opinion on the question: ... should I buy the I7 or upgrade to an I9?
For the price/performance it‘s a nobrainer... don’t do it. The cpu performs up to about 10% faster. But the cpu only defines a part of the overall performance of the complete system (other parts are also important: GPU, memory, SSD, bus structure/speed etc.). So the overall system performance gain is likely to be limited to less than 5%.
But 10 cores sounds/feels good. And after a couple of years you might get a better price for your iMac. I also went for the full tuning for my Italian Giulia from 280 to 320 hp. It’s totally useless (100 km/h speed limit) , but I love it 😎.
Whatever configuration you choose, good luck and be happy with your new iMac 2020👌
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Which model Giulia do you have? I was just looking at some Stelvios with the same 280bhp engine and wondered how much difference would a remap make. An extra 40bhp should be quite noticeable. What's amazing is that the humble 200bhp engine can also be tuned to 320 hp! Maybe that's the best solution for low cost and insurance purposes
I really would love to get a Guilia Quadrifoglio and 3 years ago I very nearly did but common sense kicked in and I gave it a pass as the car was too much of an unknown quantity regarding reliability and residuals at the time. I test drove both a 280bhp Veloce and the Quad and it was no comparison. The Veloce was nice and handled well but lacked all the drama and fun of trying to tame that wild Quadrifoglio and it's 500+ horses, the car kicked so much at every turn it was like riding a bucking bronco and the noise she made was incredible. It was wet and windy when I had the test drive but I spent most of it with the window down so I could hear the engine and exhaust roar.
Anyway back to the iMac, I've been using an i7 iMac 2020 for almost a week now and performance is good, much better then using a 16 inch MBP i9 which thermal throttled like crazy. Running FCP and and using neatvideo plugin the MBP 16 inch would thermal throttle down to 1.5ghz from a base of 2.4ghz while the i7 iMac keeps things running at over 4ghz. Only downside is that the AMD graphics card in the iMac doesn't seem to be supported by neat video so it's only using the CPU. Hopefully this will change as they add support.
Geekbench 5 on the 16 inch i9 MBP with 32gb ram out of the box scored 7000 multicore while the iMac i7 with only 8gb ram scored 7500. I added an 8gb stick of ram to it and its score went up to 7880, would probably be higher if I added matching pairs of 8gb sticks rather then 3 sticks of 2x4gb and 1 8gb, in which case I would expect scores to hit above 8000. But geekbench is a synthetic benchmark that lasts about 1 minute so doesn't take into account thermals in which case I'm sure the difference between the 16 inch MBP i9 8 core and the iMac i7 8 core would be much greater.
As for i7 vs i9 iMac, I suspect the thermals of the iMac would severely limit that i9's ability to stretch it's extra legs out over the i7 in a pure speed test. The extra 2 cores would come in handy if you're running lots of virtual machines, running multiple intensive apps e.g rendering in FCPX while exporting another project in Compressor, or using something that multi-thread such as Handbrake.
Speaking of Handbrake, using the Cpu to compress video is marginally faster in the windows version under bootcamp compared to using it on mac. The 5500xt also seems to export a little bit faster in windows under AMD VCE settings compared to when the AMD card is used by videotoolbox in MacOs. Under bootcamp, using handbrake to export h265, the AMD 5500xt was faster then an Nvidia 2070 super thunderbolt 3 EGPU. I would expect the 2070s would outperform the 5500xt had it not been constricted by the thunderbolt 3 interface. Did a load of test and benchmarks which I will writeup in a thread I made before about the iMacs and eGPUs.
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