Can the storage in the 2017 imac be upgraded with a larger drive

ok.. I'll have to try that... I need to be convinced an External SSD is as fast as an internal one.

But you have not told us which the three drive options you now in your iMac, and that definitely affects how to proceed.

• Apple mechanical hard drive
• Apple hybrid "Fusion" drive
• Apple pure SSD.

Pertinent points:

• Only if the computer came with a Fusion Drive or the Apple SSD does the logic board have a slot for a fast NVME or blade-type SSD.
• the factory NVME SSD option dos about 2700MB/sec ( I have a s2017 5K with thet option)
• A healthy Fusion drive in your model is far faster than either an internal or external SATA-6 SSD. Nominal Fusion speeds in the 2017 27-inch iMac are Writes at 600-900MB/sec and Reads between 1300 and 2000MB/sec.
• An internal SATA-6 SSD will do 500 MB /sec or a little better.
• An external NVME SSD in a Thunderbolt 3/4 enclosure set as the boot volume can be nearly as fast as the internal NVME SSD
• An external SATA-6 SSD in as USB-3 enclosure set as the boot volume maxes at about 400MB/sec.

So please help us provide you with the best answer based on your equipment. What drive option is currently in your iMac, and have you run speed tests? I prefer the drive performance tests in EtreCheck because a) I have a database of EtreCheck results, and b) Etrecheck will not reveal any personal information.

https://etrecheck.com/index

The free version will do nicely for this purpose, although the app is worthy of our financial support.

We can see hard data about drive performance, software issues, and RAM usage. Etrecheck is the development of a long-serving and trusted contributor here expressly for displaying information in these forums to help us help you by remotely evaluating Mac issues. It will not reveal any personal or secure information.

Please see this excellent user tip on how to post long text reports like EtreCheck's into a forum response:

How to use the Add Text Feature When Post… - Apple Community

Etrecheck will also pick up other factors contributing to slow performance, like ill-advised anti-virus and so-called "cleaning" apps.

Then add an external SSD! To do so is dead easy by following the directions in How to setup an external SSD as your startup disk. The SSD I'd recommend to get the best performance is a https://eshop.macsales.com/shop/owc-envoy-pro-sx

It simply does not make sense to open a 2017 iMac which is far more complex than a 2010 or 2011 iMac. Don't believe me, look at the videos on https://eshop.macsales.com/installvideos. Again, far easier, more reliable and dead simple to do rather than doing complex surgery.

Yes your 2017 iMac 27" internal drive (most were Fusion drives) is potentially replaceable, but the question is why? I've opened up & (successfully) changed drives in iMacs and agree 100% with rkaufmann87......It is a real PITA & just ain't worth it over using external drive(s). I second that excellent link for step-by-step instructions on setting up an ext SSD as a startup drive. Use an external SSD as your startup disk … - Apple Community

OTOH- IF you have a burning desire to do some 'Mac Surgery', you should watch this video at least 4-5 times before cutting into your iMac- https://eshop.macsales.com/installvideos/imac_27in5k_14late_hdd/iMac17-1/

FWIW- When my 2019 iMac's internal drive died recently I went the ext SSD route. In daily use the speed difference between an using an internal vs external (via Thunderbolt port) SSD is quite minimal. I see no reason to waste the time/effort/expense to install an internal SSD on a mid-to-late life cycle iMac.

Yes, but it's a silly thing to do when adding an external drive is so much easier, less expensive and simple to do!

Unlike a 2010-2011 iMac, 2017 iMacs have 10Gbps USB 3.1. An external USB-C SSD (800-1000MB/s typical) is potentially faster (than a direct SATA HDD->SSD upgrade).

I am looking at System Information on my 2017 27" 5K iMac and it shows USB 3.0 5GBps.

Same with the 2017's listing in the MacTracker database. Mactracker suggest that the 10GBps USB 3.1 did not appear in iMac until the M1 iMacs.

The internal HDD uses a SATA 6Gbps connector. This limits a direct SATA SSD replacement to 6Gbps (500-600MB/s max typical).

Unlike a 2010-2011 iMac, 2017 iMacs have 10Gbps USB 3.1. An external USB-C SSD (800-1000MB/s typical) is potentially faster (than a direct SATA HDD->SSD upgrade).

rachorg wrote:

I have a 27 inch imac (2017) with a 1 TB hard drive inside. Can that drive be replaced with a larger drive? Is the drive replaceable?

If you have a healthy working internal fusion drive, I would follow the instructions provided for an external SSD. I suggest looking at the offerings from OWC but other makers (Samsung and others) have reliable models. I would purchase one of those rather than put a bare SSD in an enclosure myself.

If you choose to replace the internal drive with a new SSD, I would have it done by an Apple Authorized Service Provider. You will get a warranty with such work and technicians experienced with such intricate work will perform it.

I believe that for the 2017 iMacs, only the 2 and 3 TB Fusion Drives came with 128 GB of flash storage. The 1 TB Fusion Drives came with only 32 GB. Even though that 32 GB of flash memory is a lot faster than any USB/SATA SSD, there isn't very much of it.

The USB 3.0 bus is for the USB-A ports.

For USB 3.1 speed connect a USB device to a Thunderbolt 3/USB-C port. (USB 3.1 is a fallback/alt-mode protocol on TB3 host ports)