Upgrading an iMac Pro to 256GB of RAM Only Possible at Time of Purchase [Updated] - MacRumors
Skip to Content

Upgrading an iMac Pro to 256GB of RAM Only Possible at Time of Purchase [Updated]

Update: Despite what Apple's internal document stated, OWC has released an aftermarket 256GB memory upgrade kit for the iMac Pro for $2,499.



Last week, Apple added a 256GB RAM configure-to-order option for the iMac Pro. Unfortunately, if you already purchased an iMac Pro with 128GB of RAM or less, upgrading to 256GB does not appear to be possible.

imac pro white background
The new 256GB RAM option consists of four 64GB memory modules, and in an internal document distributed to Apple Stores and Apple Authorized Service Providers, Apple states that the new configured-to-order ‌iMac‌ Pro is the only model designed to work with those 64GB memory DIMMs. No reason is provided.

This information suggests that Apple Authorized Service Providers will not be able to upgrade an ‌iMac‌ Pro to 256GB of RAM, nor will third-parties like OWC. In other words, purchasing an ‌iMac‌ Pro with 256GB of RAM will only be possible via the CTO option on Apple's online store during the checkout process.

256GB of RAM is a $5,200 upgrade option on Apple's online store, in addition to the ‌iMac‌ Pro's base $4,999 price.

The standard ‌iMac‌ is a bit more fortunate, as OWC has confirmed that the new 27-inch models released last week can be upgraded with up to 128GB of RAM, despite maxing out at 64GB on Apple's online store.

Related Forum: iMac

Popular Stories

Dynamic Island iPhone 18 Pro Feature

11 Reasons to Wait for the iPhone 18 Pro

Monday May 11, 2026 9:01 am PDT by
We're only four months out from the launch of Apple's premium next-generation smartphone lineup, and while we're not expecting a sea change in terms of functionality, there are still several enhancements rumored to be coming to the iPhone 18 Pro and iPhone 18 Pro Max. One thing worth noting is that Apple is reportedly planning a major change to its iPhone release cycle this year, adopting a...
iOS 26

iOS 26.5 Features: Everything New in iOS 26.5

Monday May 11, 2026 5:09 pm PDT by
Apple released iOS 26.5 after a few months of beta testing, and while it doesn't have the Siri features we were hoping for since those are being held until iOS 27, there are a handful of useful changes worth knowing about. Subscribe to the MacRumors YouTube channel for more videos. End-to-End Encryption for RCS Support for end-to-end encryption (E2EE) for RCS messages between iPhone and...
General Apps Reddit Feature

Reddit Starts Blocking Mobile Website, Pushing Users to App Instead

Monday May 11, 2026 6:10 am PDT by
Social network Reddit recently began blocking mobile visitors to its website while pushing them to download the official Reddit app, and it's fair to say that the move is not going down well with users. If you visit reddit.com on your iPhone today, you may see a new popup that can't be dismissed, asking you to "get the app to keep using Reddit." A Reddit spokesperson told Ars Technica...

Top Rated Comments

PinkyMacGodess Avatar
93 months ago
Should Apple retire the 'Pro' name. It's obvious they can't deliver. Sad, really... And I cling to my Macpro4,1 hoping it lasts a few more years.

EDIT: My point is that 'Pro's' need flexibility. If there is no physical way to upgrade the system, then it's either buy top of the line, or look elsewhere. The closed agenda has to be costing them some users, one would think...
Score: 36 Votes (Like | Disagree)
93 months ago
Surprise! Who'd have thought Apple would pull more of this ****?!
Score: 29 Votes (Like | Disagree)
falainber Avatar
93 months ago
Oh no! Limited to a plebian 128GB of RAM on the most RAM-efficient OS available! What ever will we do? /s
In desktops, RAM is mostly needed for apps not OS.
Score: 27 Votes (Like | Disagree)
PinkyMacGodess Avatar
93 months ago
"Pro" stands for "proficient"
Or 'PROfit' as people have to upgrade to get more memory?
Score: 22 Votes (Like | Disagree)
Plutonius Avatar
93 months ago
I'm not sure what professionals are in the market for an iMac Pro if they need 256 Gig. Until Apple comes out with a revised Mac Pro, I would probably looking at non-Apple solution for a lot less money.
Score: 21 Votes (Like | Disagree)
BaccaBossMC Avatar
93 months ago
Oh no! Limited to a plebian 128GB of RAM on the most RAM-efficient OS available! What ever will we do? /s
Score: 17 Votes (Like | Disagree)