Imac boot up has become very slow

[gyht]

Hi, I've got a iMac 2015 i7 CPU with a 1 TB Samsung SSD & 16 gb RAM. It takes forever (10 - 15 mins or more) to boot up into the login screen. After going in, it works ok but hangs now and then. It also did a random shutdown when trying to reformat the HDD and reinstall OS to El Capitan. After that, it could not detect the HDD and I sent it to the repair shop.

At the repair shop - they reformatted the SSD and checked the motherboard, and said it might be the CPU. Apple hardware tests reveal that the motherboard and HDD are ok. But after all this, the slow start up remains. Any suggestions for what could be done? The SSD is under a year old.

I have lower spec'd iMac 2015 models that boot up super fast in comparison. This isn't normal. Just wondering if it might be salvageable or not.

Thanks in advance for any advice.

 

[Cory Cooper]

Hello,

• Is this an iMac (Retina 4K, 21.5-inch, Late 2015) or iMac (Retina 5K, 27-inch, Late 2015)?
• Is the 16 GB RAM Apple OEM, third-party, or a mixture?
• Did this issue begin when installing the SSD and/or adding RAM?
• Is this slowness after a clean install, without adding any software?
• Are there a lot of Login Items or applications that automatically launch at startup?
• Have you tried installing macOS on an external drive and see if that slowness occurs when starting up from an external drive?

C

 

[gyht]

Hi Cory

See below:

iMac (Retina 4K, 21.5-inch, Late 2015)
16 GB RAM Apple OEM

• Did this issue begin when installing the SSD and/or adding RAM?
  
  The new SSD is under a year old - it was replaced a year ago because I faced a similar issue. The computer failed and was unable to install / upgrade the OS.
  
• Is this slowness after a clean install, without adding any software?
  
  Yes, reformat and clean install
  
  
• Are there a lot of Login Items or applications that automatically launch at startup?
  
  Not relevant now as we have just done a complete reformat running El Capitan.
  
  
• Have you tried installing macOS on an external drive and see if that slowness occurs when starting up from an external drive?
  
  Have asked the shop to check.
  
  Thanks

 

[jazzwineman]

Hi Cory

See below:

iMac (Retina 4K, 21.5-inch, Late 2015)
16 GB RAM Apple OEM

• Did this issue begin when installing the SSD and/or adding RAM?
  
  The new SSD is under a year old - it was replaced a year ago because I faced a similar issue. The computer failed and was unable to install / upgrade the OS.
• Is this slowness after a clean install, without adding any software?
  
  Yes, reformat and clean install
  
  
• Are there a lot of Login Items or applications that automatically launch at startup?
  
  Not relevant now as we have just done a complete reformat running El Capitan.
  
  
• Have you tried installing macOS on an external drive and see if that slowness occurs when starting up from an external drive?
  
  Have asked the shop to check.
  
  Thanks

After boot have you run a utility to see what the actual CPU speed is and the HD read/write is. If not I would start there. What did
they do to check out the motherboard? Clearly this has to be a hardware issue.

TBB in Dallas

 

[gyht]

The shop fixed the motherboard and all is back to normal. Hope it holds up. Thanks to all for your advice.