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

AirPods Pro Firmware Feature

Apple Releases New Firmware for AirPods Pro 2, AirPods Pro 3, and AirPods 4

Thursday November 13, 2025 11:35 am PST by
Apple today released new firmware designed for the AirPods Pro 3, the AirPods 4, and the prior-generation AirPods Pro 2. The AirPods Pro 3 firmware is 8B25, while the AirPods Pro 2 and AirPods 4 firmware is 8B21, all up from the prior 8A358 firmware released in October. There's no word on what's include in the updated firmware, but the AirPods Pro 2, AirPods 4 with ANC, and AirPods Pro 3...
Tim Cook WWDC 2018

Report: Tim Cook to Step Down as Apple CEO 'as Soon as Next Year'

Saturday November 15, 2025 2:40 pm PST by
Apple is preparing for Tim Cook to step down as CEO of the company "as soon as next year," according to the Financial Times. The company's board of directors and senior executives "recently intensified preparations for Cook to hand over the reins," the report said. While the report said that Apple is unlikely to name a new CEO before its next earnings report in late January, it went on to ...
iPhone Pocket Short

iPhone Pocket Now Available to Order, But Already Selling Out

Friday November 14, 2025 6:20 am PST by
Apple recently teamed up with Japanese fashion brand ISSEY MIYAKE to create the iPhone Pocket, a limited-edition knitted accessory designed to carry an iPhone. iPhone Pocket is available to order on Apple's online store starting today, in the United States, France, China, Italy, Japan, Singapore, South Korea, and the United Kingdom. However, it is already completely sold out in the United...
apple silicon mac lineup 2024 feature purple m5

Apple's 2026 Mac Plans

Friday November 14, 2025 3:23 pm PST by
Most of Apple's Macs are slated to get M5 chips across 2026, and there's a possibility we'll even see the first M6 chips toward the end of the year. Updates are planned for everything from the MacBook Air to the Mac Studio. MacBook Air (Early 2026) The MacBook Air will be one of the first Macs to get a 2026 refresh, with an update planned for the first few months of the year. The MacBook...
best early black friday deals

Best Black Friday Apple Deals Live Now - Save on AirPods, iPads, and Apple Watches

Saturday November 15, 2025 1:45 pm PST by
We're officially in the month of Black Friday, which will take place on Friday, November 28 in 2025. As always, this will be the best time of the year to shop for great deals, including popular Apple products like AirPods, iPad, Apple Watch, and more. In this article, the majority of the discounts will be found on Amazon. Note: MacRumors is an affiliate partner with some of these vendors. When ...
tvOS 26 Profiles

tvOS 26.2 Adds a Useful New Feature to Your Apple TV

Friday November 14, 2025 10:02 am PST by
Starting with the upcoming tvOS 26.2 update, currently in beta, additional profiles created on the Apple TV no longer require their own Apple Account. In the Settings app on the Apple TV, under Profiles and Accounts, anyone can create a new profile by simply entering a name and indicating whether the profile is for a kid. The profile will be associated with the primary user's Apple Account,...
walmart new ornametns

Walmart Black Friday Deals Begin Today With Low Prices on Headphones, TVs, and More

Friday November 14, 2025 7:55 am PST by
Walmart's Black Friday sale has officially kicked off today, with an online shopping event that's also seeing some matching deals in retail locations. There are quite a few major discounts in this sale, including savings on headphones, TVs, and more. Note: MacRumors is an affiliate partner with Walmart. When you click a link and make a purchase, we may receive a small payment, which helps us...
CarPlay Pinned Messages

iOS 26.2 Adds New CarPlay Setting

Thursday November 13, 2025 6:48 am PST by
iOS 26 extended pinned conversations in the Messages app to CarPlay, for quick access to your most frequent chats. However, some drivers may prefer the classic view with a list of individual conversations only, and Apple now lets users choose. Apple released the second beta of iOS 26.2 this week, and it introduces a new CarPlay setting for turning off pinned conversations in the Messages...
iOS 26

Everything New in iOS 26.2 Beta 3

Monday November 17, 2025 3:20 pm PST by
Apple provided developers with the third beta of an upcoming iOS 26.2 update, and there are still new features that are being added with each beta that we get. We've rounded up all of the changes that Apple made in beta 3. AirDrop Apple added new AirDrop functionality, providing a way for two people to share files temporarily without having to add one another as contacts. iOS 26.2...

Top Rated Comments

Spanther Avatar
58 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
58 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
58 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
58 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
58 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
58 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)