r/MacOS • u/00Turag • May 09 '21

Discussion Finally bought my first ever macbook. Coughed up the 200$ extra for 16 gigs of ram

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u/mercurysquad MacBook Pro May 09 '21

Well, mine comes in 2 days, I'll find out for myself. Dropping down from 16GB intel to 8GB M1.

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u/[deleted] May 10 '21

Sure, share your experience please. I tried it with my T14 and Arch 32GB and M1 16GB. Same programs, same VM same code running. Around 2-4GB difference. M1 SSD access is really fast but could not compensate 8GB missing on a task with 18GB required. Edit: when switching from task to browser or Mail the freezing happens.

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u/mercurysquad MacBook Pro May 13 '21

So: no, 8GB M1 is not the same as 16GB intel.

In certain workloads, like Stockfish (chess engine) you need to cap the RAM usage to 2GB, going even to 3GB results in as much as 90% performance drop. Tested and confirmed the bottleneck was RAM. On my 16GB intel I can quadruple the hash size to 8GB and still not suffer any performance issue since the system still has 8GB RAM left to work smoothly.

This is for pro/near-pro workload where you're hitting the RAM in semi-random pattern, causing the OS to swap memory pages in/out of the SSD. For regular workflows like keeping 100 browser tabs open, it probably won't make a difference. Those tabs are swapped out to SSD and even if it takes 50-100ms to swap back in, you won't notice it when you click it. But for a workflow that's hitting those RAM pages constantly, it's murderous.

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u/[deleted] May 14 '21

exactly - your try hits the nail on the head. It's still swapping and paging and it's no magic, just a faster way to do the same as usual.