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Did you just set this up? If it’s still syncing with the cloud and spotlight indexing. It’ll be a bit laggy.
 
FWIW my MacBook Air 2020 Intel can be laggy too, especially when it comes to system animations etc. But then again I do have a lot of crap installed on it too. Perhaps if you try a new user account or boot up in safe mode, see if things are any speedier?
 
I recently purchased a 2020 MBA Intel I7, 16GB, 1TB and it seems slower than my 2012 iMac 2012 Intel I7, 32GB, 1 TB SSD.

The MacBook Air uses a CPU optimized for battery life while the iMac uses a CPU optimized for performance. So even though the iMac's CPU and iGPU are eight years older, they have higher clock speeds than the Air and can hold that speed longer due to better cooling. The Air's memory bandwidth is about double that of the iMac's, so anything memory-intensive will likely be much faster on the Air.
 
The 13.3" MacBook Pro does use a more powerful CPU than the Air so performance should be noticeably better than the iMac based on the Geekbench scores (which are about 50% better in Single and Multiple Core).
 
I recently purchased a 2020 MBA Intel I7, 16GB, 1TB and it seems slower than my 2012 iMac 2012 Intel I7, 32GB, 1 TB SSD.

I am running Safari and Excel on both and on the MBA it is just laggy in comparison.

I used the migration assistant to set up the MBA. Running current OS on both with all of the updates.

Thoughts? What can I run to objectively compare the two?
My hypothesis on this from own experience, is that Intel has released lots of updates to counter side channel attacks, which has resultet in lots processor optimization being disabled. Since the 2012 iMac is out of support, it has not recieved these crippling updates.

I have a 2014 11” i7 8GB/512GB MBA still supported and on latest macOS, which has become noticable slower compared to my late 2009 27” i7 imac. Which runs as fast as ever. The iMac does have 4cores and 24GB, but much slower ssd (on paper). The processor in the MBA is a newer design with 1,5x the single core performance (at least it once had, haven’t tested recently), so roughly the MBA over iMac performance was 50% better at single threaded tasks and 50% worse in multithreaded tasks. But now it is just slow slow slow compared to the iMac still, which still feels like a modern machine with power to spare.

I wonder if downgrading the MBA to High Sierra (the version my iMac is running) will regain its performance. (That will not be possible on your 2020 machine)
 
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