2017 Imac Fusion to SSD Upgrade. How fast it should be?

Hello,

Your Fusion Drive configuration combines a fast, 128GB SSD with a larger 2TB hard disk, and even for more demanding workloads, this specific high-end Fusion Drive configuration typically provides great performance, so I'm sorry to hear you're not seeing that.

To see what might be going on with yours before upgrading to an external SSD, I believe we need to proceed with an EtreCheck report. EtreCheck is a useful App to diagnose and identify issues, both hardware and software. It is trusted by many users. Please follow the steps outlined below:

1. Navigate to: https://etrecheck.com and get the free version of EtreCheckPro.

2. Download it. It is a free and trusted app. It is often recommended here on Apple Support Communities.

3. Open EtreCheck, and before running the report, be sure to check “Allow full Drive Access” at the bottom of the EtreCheckPro window.

4. Run the report, and put it in a post, as shown here: https://discussions.apple.com/docs/DOC-250000211. We will then examine the report for issues in your Mac.

Jack

Your current Fusion drive setup shows this for speeds:

Performance:

System Load: 1.95 (1 min ago) 2.23 (5 min ago) 2.06 (15 min ago)

Nominal I/O usage: 0.70 MB/s

File system: 20.75 seconds

Write speed: 431 MB/s

Read speed: 2321 MB/s

Read speed is excellent but I feel the Write speed is below nominals. (I collect iMac drive speed reports). Most Fusion drives in 27-inch iMacs will do Writes at 600-1000MB/sec, sometimes more.

If you replace the mech SATA hard drive with a 2.5-inch SATA 6G SSD, your overall speed will probably plummet. The fastest transfers it can manage on a 6G SATA bus is about 500MB/sec. You'll lose that lovely fast Read speed.

And you don't want to be cracking open a sealed case iMac anyway.

I see Time Machine is not configured. As the symptoms may portend portend a failure, you MUST make backups immediately if you have not!

You have a lot of software I do not recognize but I do not see the "usual suspects" know to slow hard drives.