Custom Built 21.5-inch iMac with Intel Core i9 Outperforms 24-inch M1 iMac in Tests

Despite its impressive performance, the new 24-inch iMac powered by the M1 Apple silicon chip, a new project shows that upgrading a previous-generation 21.5-inch ‌‌iMac‌‌ with an Intel Core i9 processor can deliver similar or even better performance.



The new 24-inch ‌iMac‌ is up to 56% faster than the previous generation 21.5-inch ‌iMac‌ with an Intel processor, which it is replacing. The current highest-end 21.5-inch ‌iMac‌ available features an Intel Core i5 processor, but the desktop computer was previously offered with an Intel Core i7.

Now, taking matters into his own hands, Apple YouTuber Luke Miani, in his latest video, decided to outfit the previous generation 21.5-inch ‌iMac‌ with Intel's latest Core i9 processor. A configuration never offered by Apple officially.

Out of the box, the 21.5-inch ‌iMac‌ featured the Intel Core i3 8100 processor, 8GB of RAM, the Radeon Pro 555X graphics card, and 256GB of SSD storage. Miani himself upgrades the ‌iMac‌ to include the Intel Core i9 9900 and 32GB of RAM. All in all, including the upgrades, the 21.5-inch ‌iMac‌ costs $1,250. In contrast, the baseline 24-inch ‌iMac‌ with 8GB of RAM used in the comparison costs $1,299.

In initial tests focused on graphics, such as Geekbench 5, the ‌M1‌ ‌iMac‌ outperforms the custom 21.5-inch ‌iMac‌ with a score of 7,700, compared to the Intel Core i9 scoring 7,400. In Geekbench tests for computing, the ‌M1‌ ‌iMac‌ scores 20,000 compared to the 21.5-inch ‌‌iMac‌‌ featuring the Radeon Pro 555X, receiving a score of 15,789.

In more computing-centric tests, such as Cinebench, the Intel Core i9 scores 9,214, compared to the roughly 7,500 scores for the ‌M1‌ ‌iMac‌. In a Blender render test, the ‌M1‌ ‌iMac‌ takes around six minutes to render a sample project, while the custom-built 21.5-inch ‌iMac‌ completes the render in three minutes and thirty seconds. It's worth noting, however, that Blender on ‌M1‌ is running through Rosetta emulation, meaning there is a slight drawback in performance.

The full video by Miani is a great watch for those interested in possibly upgrading their own ‌iMac‌ with improved RAM, and a more powerful processor.

Popular Stories

iOS 26 on Three iPhones

iOS 26's Liquid Glass Design Draws Criticism From Users

Wednesday September 17, 2025 2:56 pm PDT by
It's been two days since iOS 26 was released, and Apple's new Liquid Glass design is even more divisive than expected. Any major design change can create controversy as people get used to the new look, but the MacRumors forums, Reddit, Apple Support Communities, and social media sites seem to feature more criticism than praise as people discuss the update. Complaints There are a long...
iPhone 17 Pro and Air Feature

Two iPhone 17 Pro and iPhone Air Colors Appear to Scratch More Easily

Friday September 19, 2025 10:02 am PDT by
As reported by Bloomberg today, some of the new iPhone 17 Pro and iPhone Air models on display at Apple Stores today are already scratched and scuffed. French blog Consomac also reported on this topic. The scratches appear to be most prominent on models with darker finishes, including the iPhone 17 Pro and Pro Max in Deep Blue, and the iPhone Air in Space Black. Images Credit: Consoma ...
iOS 26

iOS 26.0.1 Coming Soon, Likely With iPhone Air and iPhone 17 Pro Fix

Thursday September 18, 2025 9:17 am PDT by
Apple is preparing to release iOS 26.0.1, according to a private account on X with a proven track record of sharing information about future iOS versions. The update will have a build number of 23A350, or similar, the account said. It is likely that iOS 26.0.1 will fix a camera-related bug on the new iPhone Air and iPhone 17 Pro models. In his iPhone Air review, CNN Underscored's Henry T. ...
M6 MacBook Pro Feature 1

Apple's Rumored MacBook Pro Redesign: 6 New Features Anticipated

Wednesday September 17, 2025 4:26 am PDT by
Apple in October 2024 overhauled its 14-inch and 16-inch MacBook Pro models, adding M4, M4 Pro, and M4 Max chips, Thunderbolt 5 ports on higher-end models, display changes, and more. That's quite a lot of updates in one go, but if you think this means a further major refresh for the ‌MacBook Pro‌ is now several years away, think again. Bloomberg's Mark Gurman has said he expects only a small ...
iOS 26

iOS 26.1 to iOS 26.4: Here Are 5 New Features to Expect on Your iPhone

Tuesday September 16, 2025 11:17 am PDT by
iOS 26 was finally released on Monday, but the software train never stops, and the first developer beta of iOS 26.1 will likely be released soon. iOS 18.1 was an anomaly, as the first developer beta of that version was released in late July last year, to allow for early testing of Apple Intelligence features. The first betas of iOS 15.1, iOS 16.1, and iOS 17.1 were all released in the second ...
Tim Cook Rainbow

Apple Reportedly Plans to Launch These 10 Products in 'Coming Months'

Sunday September 14, 2025 8:45 am PDT by
Apple's annual September event is now in the rearview mirror, with the iPhone 17, iPhone 17 Pro, iPhone 17 Pro Max, iPhone Air, Apple Watch Series 11, Apple Watch Ultra 3, Apple Watch SE 3, and AirPods Pro 3 set to launch this Friday, September 19. As always, there is more to come. In his Power On newsletter today, Bloomberg's Mark Gurman said Apple plans to release many products in the...

Top Rated Comments

Spanther Avatar
56 months ago
One-off, pimped-out, hand-built Jeep Wrangler Rubicon outperforms factory spec Wrangler Sport in Moab.

News at 11.
Score: 71 Votes (Like | Disagree)
Sebosz Avatar
56 months ago
This brings one interesting thing about these new iMacs - their prices. I know it’s been said many times, but the fact that Apple is offering a 256/8 configuration for $1250 is just absurd. I’ve seen phones with more memory. Or let me put it this way - the money they ask for upgrading these is sick, especially now when nothing in these devices is user-upgradable. It’s just ridiculous.
And before someone says “if you don’t like it don’t buy it” - I’d love to buy one, but I’m not gonna pay 2x more just because I want a 16/1024 configuration.
Score: 54 Votes (Like | Disagree)
macsplusmacs Avatar
56 months ago
This thread is now being drowned out by the noise of the I9's cooling system......
o_O
Score: 45 Votes (Like | Disagree)
fenderbass146 Avatar
56 months ago
okay? Some guy dropped a **** load of money and time to do a mod and it just barely out performs the new entry level
Score: 44 Votes (Like | Disagree)
Andres Cantu Avatar
56 months ago
Lots of salt around the comments. It’s just a project people, not meant to be replicated by the average person who’d just buy the M1.

There’s people out there that appreciate the effort and coolness factor for things like these.
Score: 36 Votes (Like | Disagree)
Rudy69 Avatar
56 months ago

[HEADING=2]Custom Built 21.5-inch iMac with Intel Core i9 Outperforms 24-inch M1 iMac in Tests[/HEADING]
Every single tests in the article was won by the M1 except Cinebench......Who wrote this title?
Score: 30 Votes (Like | Disagree)