iMac late 2015 very slow

HerzerSkerzer wrote:

Hello D.I. Johnson,

thanks for your reply.

...

On the 4th point: do you mean using the external drive as a unique and main drive or only as a drive for the operating system and keeping documents in the actual one? What's your opinion regarding a brand new HD for the machine?

You're welcome.

Re: point 4, were this my machine and I've determined the internal drive to be failing, I'd get an external SSD and make that my main working drive. I'd install the latest macOS the iMac can run - 12 Monterey - and make that my startup drive. The OS will default to using it for the user home folder and data storage. The connecting point will be Thunderbolt/USB-C and would provide more than adequate bandwidth for normal everyday use.

You might make a detailed evaluation of the drives with the DriveDX utility from BinaryFruit.

As for what brand of drive, I'd start by looking at the SSD and HDD offerings at OWC/macsales. They are an often recommended retailer here in the Community and can provide guidance specific to your Mac and situation if you call them.

If you're asking about replacing the internal hdd, then I'd also suggest taking a look at OWC/macsales' guidance online including vids. I'm not sure exactly what the job would require as far as tearing down that particular iMac. It may be daunting and best left to a pro, but if you have the desire and the tools you may be able to DIY.

Should you try the external ssd route, remember that the external drive can always be repurposed for use with a newer Mac when you finally decide to replace your ten year old vintage, soon-to-be-obsolete, iMac. 👍🏽

This is pretty much as bad as it can get:

Performance:

System Load: 2.47 (1 min ago) 2.27 (5 min ago) 2.43 (15 min ago)

Nominal I/O usage: 10.65 MB/s

File system: 232.09 seconds (timed out)⚠️

Write speed: 1 MB/s ⚠️

Read speed: 42 MB/s⚠️

Based on other EtreCheck drive scores I have collected, your 2015 27-inch iMac Fusion system should be doing writes at 500-700MB/sec and Reads up to 1500MB/sec.

Apple's Fusion system consists of a smallish SSD and a conventional mech hard drive linked by software to appear and act as one drive. From the report, yours appears to still be linked, but I recommend applying the quick test in this Apple article to confirm they are acting as one:

How to fix a split Fusion Drive - Apple Support

If part of Fusion has failed, I vote for the mechanical drive component, but then I've been wrong before 😉.

Of all the useless scam-ware out there, MacKeeper is considered the archetype. It is next to impossible to completely remove. There is a utility developed by a long-serving contributor here that may be able to neuter MacKeeper. It is MalwareBytes, and please get it ONLY from the developer's site: https://www.malwarebytes.com/mac. The trial version should still work for this—it used to.

There are several problems with your Mac.

• No Time Machine backup – if you continue to use your Mac with no Time Machine or other backup strategy, then you will lose data, sooner or later.

Back up your Mac with Time Machine - Apple Support

• System Integrity Protection is disabled – re-enable this protection. Apple builds in robust system protection for a reason.

Please see: XProtect Explained: How Your Mac’s Built-in Anti-malware Software Works - How-To Geek

• Mackeeper AV software installed – disable this or better still, just uninstall it per the guidance from the publisher. Anti-virus, clean-up, optimizing and VPN apps are unnecessary and generally looked upon as bad for the performance of the Mac.

Please see: Protecting against malware in macOS - Apple Support

• Your hdd appears to be failing – the EtreCheck eval should take only 3-4 minutes, not 183! If, after removing MacKeeper and re-enabling the Apple security software you don't see improvement in performance, you might buy an external ssd, install macOS on that and use it as the startup drive. Community user @Jack-19 has created the following user tip on that subject:

Use an external SSD as your startup disk … - Apple Community

+1

Boy, how did I scroll right past that!? 😳