Help with older iMac

[ajinaz]

I have an older iMac (2008) that was running pretty well on El Capitan until a few months ago. It began to run incredibly slow. I mean 20 minutes to boot up and 2-5 minutes to open anything.
I ran verify on disk and it had several issues but couldn't repair because it was the boot disk without a restore.
I loaded El Capitan on a USB drive and booted from that. when I booted from the USB drive the system ran like new. In fact, I think it ran faster than when the iMac was new.
I was now able to use the disk utility to repair the internal drive. It reported that it was all repaired and I completely reformatted the internal drive and attempted to install a fresh El Capitan. However even the install took forever (6 hours) and everything still runs at a crawl.
Does the fact that it runs great using external and still crawls on internal point to a bad drive or am I overlooking another possibility?
Thanks in advance for any suggestions.

 

[BugeyeSTI]

Sounds like a bad hard drive..

 

[DeltaMac]

I think your hard drive is close to failing (and certainly doesn't work like new).
Everything slowing down, simply is another symptom, and means that the drive probably is really struggling to do anything at all.

Also, replacing the internal drive would make more difference than booting to the USB 2.0 bus.
You could also replace that spinning hard drive with an SSD. That would need an adapter to fill the space, but you could simply connect an SSD there, and secure it with a bit of tape. The SSD weighs very little, and in an iMac, doesn't really need much to secure it in place.

 

[Fishrrman]

Agree with others about the internal drive. It's still running, but may be getting towards the end of it's useful life.

Courses of action:
1. Open it up and replace the drive
2. Connect an external drive via USB or firewire and boot from that.
3. Start shopping for a replacement.

Something you might try:
1. Use either CarbonCopyCloner or SuperDuper to clone the internal drive to an external
2. Boot from the external
3. ERASE the internal drive
4. RE-clone from the cloned backup BACK TO the internal drive.

WHY you do this:
Over ten years, the internal drive has probably become hopelessly "fragmented" with pieces of files and free space everywhere.
Erasing the disk "wipes that out" for a clean start.
When you re-clone the backup back to the internal drive, the files should be copied "contiguously", cleaning up the file fragmentation and grouping most of the free space "at the end" of the drive.
It -might- speed it up some...