Clean Install questions (Snow Leopard & Lion)

[DJinTX]

Background info:

My aluminum MacBook (late 2008) came with Leopard, and when I first got it I ran the migration assistant to bring over all my user data (not applications) from an old PowerBook G4 that was running Tiger. Tihs previous powerbook was migrated to from an old iMac. So that was two migrations of data between multiple Macs, and no clean installs were done. Fast forward to my current MacBook, about 6 months ago I finally upgraded from Leopard to Snow Leopard.

Lately I have noticed my MacBook running a bit less "snappy" when launching apps and just general processing. I also think it is causing to e battery to drain a bit faster being that it is having a harder time finding data to process. I am not a power user, so mainly I use it for email, internet, iTunes, and streaming media to my Apple TV. In any case, it makes me think that a clean install of Snow Leopard (or maybe even Lion) might be a good idea. However I am not sure if this would help, nor how to go about it.

FYI...my 160GB HD currently has 90GB free space. Also, I regularly use time machine to back-up all my data.

Questions:

1. So, if this perceived slowness is due to the build-up of junk files on my HD, if I were to erase my HD, and then restore from my most recent time machine back-up, would it bring back these alleged junk files?

2. If we assume for the sake of discussion that I also have fragmentation, would the method described in question number 1 actually solve this fragmentation? Meaning, if there are currently large chunks of unused data scattered all over my HD causing it to perform inefficiently, is it just going to restore my HD exactly as it was, and therefore not eliminate the fragmentation problems?


Thanks in advance!

 

[jenzjen]

It should help especially given your history. I'd clean install SL and then manually copy back only the files you need.

 

[DJLC]

A clean install should help, although I would recommend manually moving stuff you need from your backup. Junk files are likely to accompany a Time Machine restore.

That said, you might try defragmenting your drive with Drive Genius. I was thinking I'd have to do a clean install, but after defragmenting I don't think I need to reinstall anymore.

 

[DJinTX]

Just so I understand your answers, it sounds like both of you are saying a clean install is a good way to go, and that running a defrag tool like drive genius might be a less intrusive way to get some results.

But, I'm still confused about clean installs and restoring from Back-up. If I back everything up and erase my HD, does it defeat the purpose of the clean install if I then restore from a time machine back-up? It sounds like from what you guys are saying that if I have junk files now, I will have them after restoring from a back-up. Is this true? Also, what about defragging? Will restoring from back-up accomplish this, or will it put everything back identical to what it is now?