6 ms·

I don't think retain/release perf has anything to do with memory consumption, but I have seen a bunch of reviews claiming that 8GB is perfectly fine. This is f

I don't think retain/release perf has anything to do with memory consumption, but I have seen a bunch of reviews claiming that 8GB is perfectly fine. This is fascinating to me, because: (a) every 8GB Mac I've used in the past has been unusably slow (b) since upgrading my 32GB Hackintosh to Big Sur, my usual 40GB working set is only about 20GB. (c) My 2015 16GB MBPr with Big Sur is also using about half as much physical memory on the same workload. Swappiness is up a little, but I haven't noticed. So my guess is that something in Big Sur has dramatically reduced memory consumption and that fix is being commingled with the M1 announce.

jdminhbg 6y ago
iPhones and iPads also have relatively small amounts of RAM compared to Android devices in the same class, so I wonder if Apple is doing something smart with offloading memory to fast SSD storage in a way that isn't noticeable to the user.
- saagarjha 6y ago
  Not on iOS.
- raphaelj 6y ago
  This is most probably more linked to Java/Kotlin vs Objective-C/Swift. Want an array of 1000 objects in Java ? You'll endup with 1001 allocations and 1000 pointers.
  - BillinghamJ 6y ago
    Pretty sure you'll end up with exactly the same in an NSArray? ObjC is excellent but it's not doing anything fundamentally magic there
    - dwaite 6y ago
      In Swift you can add value types to the heap-backed array directly, in ObjC you can use stack allocated arrays (since you have all of C) and there are optimizations such as NSNumber using tagged pointers.
      - deleted 6y ago
        [deleted]
    - mantap 6y ago
      Theoretically Java should be more memory efficient because it makes fewer guarantees and can move memory around. The advantage of Swift/ARC is not that it uses less memory per se but that it has a lower high water mark because memory is freed much sooner.
      - kllrnohj 6y ago
        > Theoretically Java should be more memory efficient because it makes fewer guarantees and can move memory around. Java makes a lot of memory guarantees that are hard to make efficient. Specifically in that it becomes extremely hard to have a scoped allocation. Escape analysis helps, but the nature of Java's GC'd + no value types means it's basically never good at memory efficiency. Memory performance can be theoretically good, but efficiency not really. That's just part of the tradeoff it's making. And nearly everything is behind a reference, making everything far larger than it could be. Compaction helps reduce fragmentation, but it comes at the cost of necessarily doubling the size of everything being compacted. Only temporarily, but those high-water spikes are what kicks things to swap, too.
    - socialdemocrat 6y ago
      Big difference is that Objective-C is a superset of C. Any Objective-C developer worth his/her salt will drop down to C code when you need to optimize. The object-oriented parts of Objective-C are way slower than Java. But the reason Objective-C programs can still outcompete Java programs is that you have the opportunity to pick hotspots and optimize the hell out of them using C code. Object-oriented programs in Objective-C are written in a very different fashion from Java programs. Java programs tend to have very fine granularity on their objects. Objective-C programs tend to have interfaces which are bulkier, and larger objects. That is partly why you can have a high performance 3D API like Metal written in a language such as Objective-C which has very slow method dispatch. It works because the granularity of the objects have been designed with that in mind.
- rsynnott 6y ago
  For those, Apple's favored approach to memory management (mostly reference counting) absolutely _is_ an advantage over Android's (mostly GC). That's not relevant when comparing an Intel and ARM Mac, tho.
megablast 6y ago
Every 8gb mac I’ve used before was fine, and that was with running Xcode, Firefox, photoshop, mail, terminal, and other programs.
- Scarbutt 6y ago
  4GB MBA user here, don't have any problems either running Chrome or Firefox with 10-20 tabs and iTerm (Safari does feel much faster than other two and my dev enviroment is on a remote server though).
- crazygringo 6y ago
  Seriously, I'm utterly baffled by all the people claiming that 8 GB isn't enough for the average user. The only situation I ever ran into where it was a problem was in trying to run multiple VM's at once. Otherwise it's just a non-issue. Programs often reserve a lot more memory than they actually use (zero hit in performance) so memory stats are misleading, and the OS is really good at swapping memory not touched in a while to the SSD without you noticing. Yes, sometimes it takes a couple seconds to switch to a tab I haven't touched in Chrome in days because it's got to swap it back in from the SSD. Who cares?
  - ianhowson 6y ago
    > people claiming that 8 GB isn't enough for the average user I'm not claiming anything of the sort. My point is that memory consumption seems to be greatly reduced in Big Sur, and that might make 8GB machines much better to use than before. All of my testing is on Intel machines. It's not exclusively an M1 phenomenon. I would still recommend 16GB to anyone, and if the extra $200 was a factor, I would recommend that they buy last year's Intel with 16GB of RAM.
    - ogre_codes 6y ago
      > I'm not claiming anything of the sort. You kind of did: > (a) every 8GB Mac I've used in the past has been unusably slow Personally, I stick to 16GB+ as well. Though my wife's Mac likely has 4GB since it's something like 8 years old and it runs just fine.
mhh__ 6y ago
> but I have seen a bunch of reviews claiming that 8GB is perfectly fine. Has anyone actually used one of these long enough to fairly compare with an x year old laptop in regular use?

jdminhbg 6y ago

iPhones and iPads also have relatively small amounts of RAM compared to Android devices in the same class, so I wonder if Apple is doing something smart with offloading memory to fast SSD storage in a way that isn't noticeable to the user.

saagarjha 6y ago
Not on iOS.
raphaelj 6y ago
This is most probably more linked to Java/Kotlin vs Objective-C/Swift. Want an array of 1000 objects in Java ? You'll endup with 1001 allocations and 1000 pointers.
- BillinghamJ 6y ago
  Pretty sure you'll end up with exactly the same in an NSArray? ObjC is excellent but it's not doing anything fundamentally magic there
  - dwaite 6y ago
    In Swift you can add value types to the heap-backed array directly, in ObjC you can use stack allocated arrays (since you have all of C) and there are optimizations such as NSNumber using tagged pointers.
    - deleted 6y ago
      [deleted]
  - mantap 6y ago
    Theoretically Java should be more memory efficient because it makes fewer guarantees and can move memory around. The advantage of Swift/ARC is not that it uses less memory per se but that it has a lower high water mark because memory is freed much sooner.
    - kllrnohj 6y ago
      > Theoretically Java should be more memory efficient because it makes fewer guarantees and can move memory around. Java makes a lot of memory guarantees that are hard to make efficient. Specifically in that it becomes extremely hard to have a scoped allocation. Escape analysis helps, but the nature of Java's GC'd + no value types means it's basically never good at memory efficiency. Memory performance can be theoretically good, but efficiency not really. That's just part of the tradeoff it's making. And nearly everything is behind a reference, making everything far larger than it could be. Compaction helps reduce fragmentation, but it comes at the cost of necessarily doubling the size of everything being compacted. Only temporarily, but those high-water spikes are what kicks things to swap, too.
  - socialdemocrat 6y ago
    Big difference is that Objective-C is a superset of C. Any Objective-C developer worth his/her salt will drop down to C code when you need to optimize. The object-oriented parts of Objective-C are way slower than Java. But the reason Objective-C programs can still outcompete Java programs is that you have the opportunity to pick hotspots and optimize the hell out of them using C code. Object-oriented programs in Objective-C are written in a very different fashion from Java programs. Java programs tend to have very fine granularity on their objects. Objective-C programs tend to have interfaces which are bulkier, and larger objects. That is partly why you can have a high performance 3D API like Metal written in a language such as Objective-C which has very slow method dispatch. It works because the granularity of the objects have been designed with that in mind.
rsynnott 6y ago
For those, Apple's favored approach to memory management (mostly reference counting) absolutely _is_ an advantage over Android's (mostly GC). That's not relevant when comparing an Intel and ARM Mac, tho.

megablast 6y ago

Every 8gb mac I’ve used before was fine, and that was with running Xcode, Firefox, photoshop, mail, terminal, and other programs.

Scarbutt 6y ago
4GB MBA user here, don't have any problems either running Chrome or Firefox with 10-20 tabs and iTerm (Safari does feel much faster than other two and my dev enviroment is on a remote server though).
crazygringo 6y ago
Seriously, I'm utterly baffled by all the people claiming that 8 GB isn't enough for the average user. The only situation I ever ran into where it was a problem was in trying to run multiple VM's at once. Otherwise it's just a non-issue. Programs often reserve a lot more memory than they actually use (zero hit in performance) so memory stats are misleading, and the OS is really good at swapping memory not touched in a while to the SSD without you noticing. Yes, sometimes it takes a couple seconds to switch to a tab I haven't touched in Chrome in days because it's got to swap it back in from the SSD. Who cares?
- ianhowson 6y ago
  > people claiming that 8 GB isn't enough for the average user I'm not claiming anything of the sort. My point is that memory consumption seems to be greatly reduced in Big Sur, and that might make 8GB machines much better to use than before. All of my testing is on Intel machines. It's not exclusively an M1 phenomenon. I would still recommend 16GB to anyone, and if the extra $200 was a factor, I would recommend that they buy last year's Intel with 16GB of RAM.
  - ogre_codes 6y ago
    > I'm not claiming anything of the sort. You kind of did: > (a) every 8GB Mac I've used in the past has been unusably slow Personally, I stick to 16GB+ as well. Though my wife's Mac likely has 4GB since it's something like 8 years old and it runs just fine.

mhh__ 6y ago

> but I have seen a bunch of reviews claiming that 8GB is perfectly fine. Has anyone actually used one of these long enough to fairly compare with an x year old laptop in regular use?