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Erase and install questions

D

Danungar

macrumors newbie
Original poster
Sep 12, 2023
16
2
I have a Macbook Air from 2010, upgraded to Sierra, that is running very slow now. The HD has tons of free space. I've tried running Onyx cleaning and maintenance routines, which helps a bit, but I'm now considering the nuclear option. Just two questions:

1) If I erase and install the OS, then retrieve all my files from iCloud Drive, is there any reason on earth why my Mac shouldn't run as fast as when I bought it?

2) If I do the above, then run Migration Assistant from a TM backup, will that carry over the gunk that is slowing down my Mac?

Thanks
 
You can try a backup/erase/re-install/restore.
It may help.
But probably not all that much.
You'll have to try it and see.

The 2010 MBA is now 13 years old.
Might be time to start shopping for a replacement.
 
Thanks, but with all due respect, you haven't answered either of my questions, which I thought were very clear. Why might it not help "all that much"?
 
Your questions can't be answered with certainty -- we don't have your Mac.
The only way you're going to know if it will run better, is to try the "refresh" and see for yourself.
 
Fair enough, but is there anything hardware-related that would slow a computer down? I don't expect it to run anywhere near as fast as a brand-new Mac, but, if all the software is clean installed, is there any reason it wouldn't run as fast as it did in 2010? (I do own a more recent Mac, but I wanted to keep the old MBA for other reasons, and not just throw it out.)
 
Danungar said:
Fair enough, but is there anything hardware-related that would slow a computer down? I don't expect it to run anywhere near as fast as a brand-new Mac, but, if all the software is clean installed, is there any reason it wouldn't run as fast as it did in 2010? (I do own a more recent Mac, but I wanted to keep the old MBA for other reasons, and not just throw it out.)
Click to expand...
If your hard drive is starting to fail, it could slow things down, and this would not be remedied by an OS reinstall. The disk starts to fail, and one consequence is that it needs to reread blocks of data multiple times in order to get one without errors. If it has to reread things 5 times, then actual data thruput is 1/5 of normal speed.

This pre-failure may be detectable if the disk's SMART status can be examined. I don't think Apple's Disk Utility can read SMART data, but I could be wrong. There are SMART utilities that run in macOS. I searched for keywords mac smart disk app and a number of results came back. You might also search the Mac App Store.

I also searched MacRumors for smart utility. These came up:

It appears DriveDx may no longer be available, but the 2nd thread discusses alternatives.
 
Thanks, I did that. The HD is fine.

I guess my question is more general in nature. Macs and computers in general tend to slow down with age. I assumed this was due to software issues, boat, bad settings, too many applications, etc. So I guess my question is whether there are any hardware-related issues that would cause a Mac to gradually slow down with age. I'm not talking about pre-failure, just sluggishness.
 
Danungar said:
Thanks, I did that. The HD is fine.

I guess my question is more general in nature. Macs and computers in general tend to slow down with age. I assumed this was due to software issues, boat, bad settings, too many applications, etc. So I guess my question is whether there are any hardware-related issues that would cause a Mac to gradually slow down with age. I'm not talking about pre-failure, just sluggishness.
Click to expand...
The only other thing I'd consider hardware-related that can occur over time is when the CPU is being throttled back for thermal reasons. That is, it gets hot and slows down to prevent overheating. I don't know whether macOS does that unless the CPU actually gets above 100°C.

The reason this might happen over time is that the heat-sink paste can dry out and become less thermally conductive. This means the temperature differential between the chip and its heat-sink is higher, so it becomes easier to hit the max CPU temp.

Disk fragmentation might be another reason for a slow-down, but that can often be remedied just by making a complete backup, erasing the disk, then restoring from the backup. Carbon Copy Cloner can do those kinds of complete backups on Sierra. A clone and restore is probably worth trying to see if it works, because it's less hassle than a reinstall and restore.

I don't think there's a significant penalty for having unused files on HFS+ disks. Other file-systems (e.g. FAT, ExFAT, APFS) don't have the same directory structure as HFS+, so someone with more expertise on those would need to reply. HFS+ uses a tree-structured directory, with pre-allocated space for directory nodes. Trees are one of the faster ways to structure name searches.
 
Thanks, that was helpful. My only remaining question is, since the slowdown is probably software-related, would running CCC or Migration Assistant not just copy over the problem ?
 
Danungar said:
Thanks, that was helpful. My only remaining question is, since the slowdown is probably software-related, would running CCC or Migration Assistant not just copy over the problem ?
Click to expand...
Not necessarily. If the problem is related to disk fragmentation in files, then copying to another disk will likely remove that fragmentation as a simple side-effect of copying.

To me, doing a copy-out, erase, copy-back are things you'd mostly be doing anyway. That is, you'd make a full backup before a reinstall anyway, so the copy-out will happen regardless. You'd erase the internal disk before a reinstall, so that's also the same. If you then do a copy-back with no other actions, you can test whether it solves the speed problems. If so, then you're done. If not, erase the disk again and go ahead with a new OS install and Migration Assistant. All you've lost is the time it took to do a copy-back. That seems like a small cost with a possibly large reward.

It depends on what you mean by "software related". If you think you have extra things running that are slowing things down, you should get evidence for that before anything else is done. If there's some other meaning for "software-related", then please clarify exactly what that is. Simply having unused files is unlikely to cause a significant slowdown in HFS+ due to its directory structure.
 
Thanks so much. I don't have the technical competence to understand it all, but I appreciate your point about using CCC (or SuperDuper, which I used to use) being less of a hassle than reinstall plus Migration Assistant. Just one quick, and hopefully last, question: does Migration Assistant, running from a TM, or, for that matter, a CCC backup, copy over less than a CCC restore?
 
Last edited:
I'd try the CCC approach first.
That may help to do what you want.

If it doesn't, THEN try the "erase, install new OS, restore" (using setup assistant).

A CCC clone (or a "Re-clone" back to the original volume) restores just about "everything".
That includes older versions of [Apple] apps, etc.

A "migration" done with setup assistant (or migration assistant) is more selective, at least with apps. It may also leave some small pieces of user data behind, not sure.
 
Danungar said:
... Just one quick, and hopefully last, question: does Migration Assistant, running from a TM, or, for that matter, a CCC backup, copy over less than a CCC restore?
Click to expand...
I don't know, but if I had to guess, Migration Assistant offers several options for what to copy in, while CCC doesn't.

You can run Migration Assistant all the way up until it right before it actually copies things into place. This lets you see what it offers without committing to anything.

A CCC backup (or restore) will basically do a verbatim copy of everything in a folder hierarchy. As I recall, it does remove files from certain system cache dirs (check Bombich website), but so will a Safe Boot.

Start up your Mac in safe mode

Starting up your Mac in safe mode may help you diagnose problems with your Mac.
support.apple.com
 
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