Why am I getting different i7 Geekbench scores than others (and why does it crash all the time)?

[Olv]

I may buy a secondhand 2020 3.8 GHz (i7-10700K) iMac which I'm checking out now.

I found that the production date was in June last year (circa months before it was released).

The multi core results I get are worse than the average (up to around 7500), but the single core results are better (around 1370). The best multi core results I've seen for the 10700K are 8878.

Ir also worries me that after a some Geekbench tests, the app crashes every time. I'm worried about buying this Mac mainly due to low multi-score results and the crashes. Good multi-results are important for me, they are important for high track counts (with sample libraries) in Logic. Any advice/comments are welcome.

 

[Nguyen Duc Hieu]

I may buy a secondhand 2020 3.8 GHz (i7-10700K) iMac which I'm checking out now.

I found that the production date was in June last year (circa months before it was released).

The multi core results I get are worse than the average (up to around 7500), but the single core results are better (around 1370). The best multi core results I've seen for the 10700K are 8878.

Ir also worries me that after a some Geekbench tests, the app crashes every time. I'm worried about buying this Mac mainly due to low multi-score results and the crashes. Good multi-results are important for me, they are important for high track counts (with sample libraries) in Logic. Any advice/comments are welcome.

Overheating + Power draw of a K CPU would lead to apps crashing and auto shutting down.
This also happens in PCs.

 

[wilberforce]

I may buy a secondhand 2020 3.8 GHz (i7-10700K) iMac which I'm checking out now.

I found that the production date was in June last year (circa months before it was released).

The multi core results I get are worse than the average (up to around 7500), but the single core results are better (around 1370). The best multi core results I've seen for the 10700K are 8878.

Ir also worries me that after a some Geekbench tests, the app crashes every time. I'm worried about buying this Mac mainly due to low multi-score results and the crashes. Good multi-results are important for me, they are important for high track counts (with sample libraries) in Logic. Any advice/comments are welcome.

I have the same iMac. Yes, you should get multicore 8500 to 9000 assuming you have at least 32GB RAM.
7500 is probably about right if you have only 8GB RAM.

What RAM do you have, and in which slots? The 2020 iMac is very finicky about RAM configuration, and installing mismatched RAM or in the wrong slots will definitely result in lower Geekbench scores. Lower geekbench can also be caused by other processes running in the background.

Geekbench has never crashed for me. Never had an overheat or auto shutdown, despite deliberately stress testing it.

 

[motrek]

Overheating + Power draw of a K CPU would lead to apps crashing and auto shutting down.
This also happens in PCs.

This is not correct. Intel CPUs will reduce their clock speed before overheating and malfunctioning. This has been the case for the past ~20 years. You can even run an Intel CPU with no cooling whatsoever. It'll run very, very slowly. But nothing will crash.

 

[Olv]

What RAM do you have, and in which slots? The 2020 iMac is very finicky about RAM configuration, and installing mismatched RAM or in the wrong slots will definitely result in lower Geekbench scores. Lower geekbench can also be caused by other processes running in the background.

Thanks for the replies.
Only 8gb, in slot 2 and 4. Seems strange to me. I will open the RAM area later and have a look, but this should be original RAM. No background operations.

 

[Olv]

Btw, I’ve only installed two apps: Geekbench 5 and Blackmagic Speed Test – which shows read/write values at around 2,4 gb/s.

 

[wilberforce]

Thanks for the replies.
Only 8gb, in slot 2 and 4. Seems strange to me. I will open the RAM area later and have a look, but this should be original RAM. No background operations.

With only 8gb ram I got about 7000 multicore.
With 32 gb I got about 8500.
With 64 gb I got about 9000 max.
Slots 2 and 4 is good.
I suggest replace the 8gb ram with 32 gb ram, i.e., 2x16gb in same slots 2 and 4, for starters. (Do not mix ram in the 2020 imac). Get another 2x16 gb identical ram for slots 1&3 if you find that is not enough.

 

[Olv]

With only 8gb ram I got about 7000 multicore.
With 32 gb I got about 8500.
With 64 gb I got about 9000 max.
Slots 2 and 4 is good.
I suggest replace the 8gb ram with 32 gb ram, i.e., 2x16gb in same slots 2 and 4, for starters. (Do not mix ram in the 2020 imac). Get another 2x16 gb identical ram for slots 1&3 if you find that is not enough.

Thanks, I’ll go for 64 or 128 gb OWC or Crucial RAM if I buy it, but after I had installed only one app and that app crashes all the time, I’m not sure what to do.

 

[wilberforce]

Thanks, I’ll go for 64 or 128 gb OWC or Crucial RAM if I buy it, but after I had installed only one app and that app crashes all the time, I’m not sure what to do.

I don't know what price you can get the used iMac, but it needs to be substantially cheaper than an apple refurb like this:

Refurbished 27-inch iMac 3.8GHz 8-core Intel Core i7 with Retina 5K display

If you can dream it, you can do it on iMac. It’s beautifully designed, incredibly intuitive, and packed with powerful tools that let you take any idea to the next level. And the new 27-inch model elevates the experience in every way, with faster processors and graphics, expanded memory and...

www.apple.com

I personally would not buy a used one unless I was 100% comfortable with it.

 

[Olv]

Agree!

Is this speed 'expected behavior' on Macs like these?

 

[wilberforce]

Here is my 2TB SSD. What is often not realized is that larger SSDs are also faster. (Furthermore, an SSD slows down as it gets near full, so avoid using more than ~90%). This is one of the reasons I got a large SSD.
So a smaller SSD can be expected to be slightly slower. Is yours 512GB or 1TB, maybe? If so, the speed looks fine to me.

 

[Olv]

Thanks, it’s circa 500 gb so that makes sense.

 

[motrek]

Thanks, I’ll go for 64 or 128 gb OWC or Crucial RAM if I buy it, but after I had installed only one app and that app crashes all the time, I’m not sure what to do.

Performance is one thing, but your computer shouldn't be crashing when you only have two bog-standard things installed. Get that sorted out.

It might be the memory. Probably the easiest thing to do is rule out the RAM. Remove one stick, see if it works without crashing. If it still crashes, try the other stick in the same slot. If it still crashes, see about returning the computer somehow...

 

[Olv]

Yes, I should try that – thanks. I've found that there's other stuff with this Mac that's not the way it should, like left half of the screen all of a sudden having another color (more pink) the the right half of the screen. That's something I've never seen on any Mac before. The best thing to do is probably just to hand it over to a certified Apple service center.

 

[wilberforce]

Yes, I should try that – thanks. I've found that there's other stuff with this Mac that's not the way it should, like left half of the screen all of a sudden having another color (more pink) the the right half of the screen. That's something I've never seen on any Mac before. The best thing to do is probably just to hand it over to a certified Apple service center.

This is likely the graphical glitch that occurs when using true tone, when shutting down or restarting, especially with the 5700XT GPU. If so, that is not something to worry about too much, as a lot of others have this. This thread, which started about a different graphical glitch (which has been resolved by a software update), also discusses this. Some people have gotten upset by it, but as far as I can tell it has not affected the normal operation. Don't know if this is the same as what you are seeing, but it sounds like it:

iMac 2020, 5700XT - graphical glitch?

While I agree, I've been an apple guy since the Apple IIe, and their stuff has always been bug-ridden as a 70-80's GM car. For a long time, I reported bugs on the developer bug reporting tool, and even got a few acknowledged and fixed but there are so many bugs I no longer provide free QA...

forums.macrumors.com

 

[Olv]

Thanks – this is different: no flickering, but exactly half the screen goes pink. I can still see what's there, but it's as if I look at the left half through a pink filter.

 

[wilberforce]

Thanks – this is different: no flickering, but exactly half the screen goes pink. I can still see what's there, but it's as if I look at the left half through a pink filter.

Yes, that is what I am talking about. One side of the screen has true tone engaged, the other not. Only happens when shutting down or restarting.

See this post for example:

iMac 2020, 5700XT - graphical glitch?

How about this? I get it during shutdown with a 2020 27" 64gb 5700XT model

forums.macrumors.com

and looks like this:

I have seen this on my 2020 iMac with 5500XT twice I think, but people with the 5700XT see it more often. It is not a reason to reject the used iMac in preference for a new one, as a brand new one will likely do the same.
It is basically an inconsequential glitch (if it only occurs during shutdown or restart), but if you are not OK with this, I suggest not get a new (or used) 2020 iMac. Or get one with the 5500XT gpu instead of the 5700XT, as it will happen much less often (but not never).
Hope this helps

 

[Olv]

Yes, that is what I am talking about. One side of the screen has true tone engaged, the other not. Only happens when shutting down or restarting.

See this post for example:

iMac 2020, 5700XT - graphical glitch?

How about this? I get it during shutdown with a 2020 27" 64gb 5700XT model

forums.macrumors.com

and looks like this:

View attachment 1861225

I have seen this on my 2020 iMac with 5500XT twice I think, but people with the 5700XT see it more often. It is not a reason to reject the used iMac in preference for a new one, as a brand new one will likely do the same.
It is basically an inconsequential glitch (if it only occurs during shutdown or restart), but if you are not OK with this, I suggest not get a new (or used) 2020 iMac. Or get one with the 5500XT gpu instead of the 5700XT, as it will happen much less often (but not never).
Hope this helps

Thanks for the help! It hasn’t happened during restart or shutdown, but i had to shut it diwn to get rid if it. If this is something which happens regularly, I’ll be needing a lot if restarts…

 

[wilberforce]

Thanks for the help! It hasn’t happened during restart or shutdown, but i had to shut it diwn to get rid if it. If this is something which happens regularly, I’ll be needing a lot if restarts…

I agree, if it happens during normal use that is not good, I wouldn't put up with that.