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Apple iMac 21.5-inch Retina 4K, Late 2015 (MK452)

Apple iMac 21.5-inch Retina 4K, Late 2015 (MK452)
alaScore 95

374 reviews

Apr, 2018

alaTest has collected and analyzed 374 reviews of Apple iMac 21.5-inch Retina 4K, Late 2015 (MK452). The average rating for this product is 4.6/5, compared to an average rating of 4.2/5 for other Desktops for all reviews. Reviewers really like the reliability and size. The design and usability are also appreciated. There are some mixed views about the price.

usability, design, size, reliability

We analyzed user and expert ratings, product age and more factors. Compared to other Desktops the Apple iMac 21.5-inch Retina 4K, Late 2015 (MK452) is awarded an overall alaScore™ of 95/100 = Excellent quality.

Review analysis

(Based on 374 reviews)

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Consumer review ( review summary for Apple iMac 21.5-inch Retina 4K, Late 2015 (MK452)


alaTest has collected and analyzed 20 user reviews of Apple iMac 21.5-inch Retina 4K, Late 2015 (MK452) from The average user rating for this product is 4.0/5, compared to an average user rating of 4.0/5 for other Desktops on People really like the design. Many are negative about the usability and reliability. There are some mixed opinions about the size.


price, reliability, usability

80% of the reviews on give this product a positive rating.

This summary is based on the products: Apple iMac MK452LL/A 21.5-Inch Retina 4K Desktop (NEWEST VERSION)Apple iMac MK452LL/A 21.5-Inch Retina 4K Desktop (NEWEST VERSION)

Apr, 2018

Expert review by : Cliff Joseph (

Apple 21.5-inch iMac with Retina 4K Display (2015) review: Display dazzles, but options are fewer


The 4K display might be something of a luxury for business users who simply want to run Microsoft Office, but the latest top-end 21.5-inch iMac will be an attractive option for users who need a fast and versatile desktop computer.

Bright, colourful 4K display ; Broadwell update provides strong processor performance ; Slimline, all-in-one design

Slow hard drive ; No longer includes discrete GPU ; Limited upgrade options

Nov, 2015

Expert review by : Mark Peters (

Apple iMac with 4K and 5K Retina Displays


New iMac comes with stunning Retina Display : Apple updated the entire iMac family, bringing a breathtaking new Retina 4K display to the 21.5-inch iMac for the first time and the Retina 5K display to every 27-inch iMac. The new Retina displays make...

The all-new Magic Keyboard, Magic Mouse 2 and Magic Trackpad 2 are more comfortable, capable and environmentally friendly. Designed around a built-in rechargeable lithium-ion battery, all three accessories eliminate the need for disposable batteries...

Oct, 2015

Expert review by : Joel Santo Domingo (

Apple iMac 21.5-Inch With 4K Retina Display (2015)


With a new Retina display, the latest Intel Core I CPU, and faster memory, the latest 21.5-inch Apple iMac is a very attractive option if you're creatively inclined and have limited space and/or funds.

Bright 4K Retina display. DCI-P3 color gamut. New rechargeable wireless peripherals. Includes Lightning cable.

No discrete graphics option. Base hard drive is only 5,400rpm. Headset jack and SD card slot are on back panel.

Conclusion If you make your living through the lens of a camera, or you're a serious creative type, the 21.5-inch 4K Retina iMac belongs high up on your short list —especially if you want the hi-res display but don't want to pay for the 27-inch 5K iMac...

Oct, 2015

Expert review by (

Apple iMac with 4K Retina display 21.5-inch, 2015


The flagship device in Apple's just-updated late-2015 iMac line is the configuration reviewed here, stepping up to a gorgeous 21.5-inch 4K resolution display and starting at $1,499 in the US (£1,199 or AU$2,099). Two other base models, at $1,099 and...

Apple upgrades the 21.5-inch iMac with a stunning 4K-resolution display, along with faster processors and Thunderbolt 2. The redesigned keyboard, mouse and trackpad all have rechargeable batteries and lightning connectors.

The new processors are still one generation behind Intel's latest and there are no discrete graphics options. No HDMI input means it can't double as a TV monitor.

The smallest Apple iMac trades up to a 4K display, and jumps to newer, but still not the latest, processors. While the design hasn't changed, newly crafted accessories with rechargeable batteries and Lightning connectors add flair and convenience.

Oct, 2015

Expert review by : Mikey Campbell (

Review: Apple's 21.5-inch iMac with 4K Retina display is great, but skip the slow HDD model


Apple's marketing team didn't need to dig deep to dream up a campaign for the new 21.5‑inch iMac with Retina 4K display -- its best feature is in the name. The stellar ultra high-resolution screen mates well with Apple's chosen internals, but it...

4K Retina display with P3 color gamut ; Powerful internals ; Small footprint

5,400 rpm HDD is a snail ; Price borders on 27-inch 5K iMac ; Slight backlight bleed at screen periphery ; Apple prices the new iMac with Retina 4K display at $1,499 for a baseline model and scales the line up to $2,399. Fortunately, a big part of what...

The 4K iMac's main draw is its gorgeous Retina display. For desktop users interested in having the best display around, the 21.5-inch 4k iMac is an easy recommendation with one caveat: it needs the HDD upgrade. An SSD would be preferable, obviously,...

Nov, 2015

Expert review by : Matt Safford (

Apple iMac 21.5-Inch With 4K Retina Display Review and Ratings


With a pixel-dense 4K display, refined design, and now-rechargeable peripherals, Apple's $1,499 compact iMac is an eye-pleasing, premium computing machine. (As good as it is, just know that the larger-screen 5K model doesn't cost that much more.)

Stunning, pixel-dense 4K display ; Bundled peripherals are now rechargeable ; Very good performance for an all-in-one

Hard drive in entry-level model makes for slow bootup, occasional sluggishness

Sure, we have our quibbles with the Magic Mouse 2's charging port, and the lack of any real internal upgradability on the system itself. But the Apple iMac 21.5-inch With 4K Retina Display is still, unquestionably, a great space-saving desktop for...

Nov, 2015

Expert review by : Stephen (

A Review of the Apple 21.5 inch iMac with 4K Retina Display


Superb color rendering with DCI-P3 color space ; Fast, powerful machine for most uses ; Beautiful design ; Wonderfully quiet, cool running ; Decent price tag ; 9.4 million pixels ; El Capitan OS X works great with 4K display

No HDMI connectivity ; Uses slightly older Intel processing chip architecture ; No discrete Graphics card technology ; Storage memory could have been more advanced

While we consider Apple’s 5K Retina iMac to be the superior machine overall, the new 4k iMac has plenty going for it and comes at a relatively reasonable price for a piece of Apple technology with such a superb integrated True 4K display. On the whole,...

Oct, 2015

Expert review by : Jason Snell (

iMac with 4K Retina display review: A high-resolution desktop Mac for the masses


The Mac is a small fraction of Apple's total business, and of that, roughly three-quarters of the Macs sold are laptops. Apple could probably be forgiven if it put the entire iMac line into maintenance mode: after all, sometimes it seems like that's...

Gorgeous Retina screen ; Thunderbolt 2 support

Fast flash-storage available as an option ; Hampered by slow 5200 rpm hard drive ; Discrete GPU available only as configuration option ; Uses previous generation Intel chipset

The 5K iMac is an incredible computer, one of the best Macs ever made—but it’s also just too much for many people. A 27-inch display can dominate a desk or a room, and though the price tag has come down a lot in the past year, it’s still on the pricey...

Oct, 2015

Expert review by : Andrew Cunningham (

Same design, new insides, better screen: 21.5-inch 4K Retina iMac reviewed


Fusion Drives desperately need to be standard, but otherwise this is a nice Mac.

Gorgeous screen with an improved color gamut ; Retina scaling modes let you use the 21.5-inch iMac to display as much information as the 27-inch iMac, a nice feature for people without much space ; Quad-core Broadwell CPUs aren't the newest on the...

No dedicated GPU options, and the integrated GPU chugs if you increase the resolution or hook up another 4K display ; No user-accessible RAM (or any user-accessible parts, really) ; No Thunderbolt 3 or USB Type-C ; No Target Display Mode ; Putting all...

The best thing about the 4K iMac is that you don't have to use a gigantic 27-inch model if you want to get a Retina display. There are plenty of people who prefer the larger screen, but for those who find it intimidating or just too big for their...

Oct, 2015

Expert review by : Kane Fulton (

Apple iMac with 4K Retina display (21.5-inch, Late 2015) review


Incredible display proves that good things come in small packages

Display ; Design ; Speakers ; Accessories

Fusion drive not standard ; Chunky display bezel

Apple's smallest all-in-one features a great design and fantastic 4K display. Just make sure you upgrade to the Fusion Drive (at the very least) for faster boot and resume times.

Jan, 2016

Product Specifications


Built-in Microphone:Y / Yes
Built-in speaker(s):Y / Yes
Built-in speakers: Yes


Energy Star certified:Y / Yes
EPEAT compliance:Bronze / Gold


Cable lock slot:No / Y / Yes
Cable lock slot type:Kensington
Color of product:Silver
Housing material:Aluminium
Wall mountable: Yes


3D compatibility: No
Aspect Ratio:1.77:1 / 16:9
Detachable display:N / No / Y / Yes
Display brightness:500
Display Diagonal:21 / 21.5 / 27
Display Resolution:4096 x 2304 / 5120 x 2880
Full HD:Y / Yes
HD type:4K Ultra HD / 5K Ultra HD
LED backlight:Y / Yes
Panel Type:IPS
Screen shape:Flat
Touch screen: No
Touchscreen:N / No

Energy Management

AC adapter frequency:50/60
AC adapter input voltage:100 - 240


Discrete graphics adapter:N / Y
Discrete graphics adapter memory:2 / 4
Discrete graphics adapter model:AMD Radeon Pro 555 / AMD Radeon Pro 560 / AMD Radeon R9 M395X / Not available
Discrete graphics memory type:GDDR5
Maximum on-board graphics adapter memory:1.7 / 1.74
Number of displays supported (on-board graphics):3
On-board graphics adapter:No / Y / Yes
On-board graphics adapter base frequency:300
On-board graphics adapter DirectX version:11.2 / 11.2/12
On-board graphics adapter dynamic frequency (max):1100 / 1150
On-board graphics adapter family:Intel Iris Pro Graphics
On-board graphics adapter ID:0x1622
On-board graphics adapter model:Intel Iris Pro Graphics 6200 / Intel® Iris™ Pro Graphics 6200
On-board graphics adapter OpenGL version:4.3


Internal memory:16 / 32 / 8
Internal memory type:DDR3-SDRAM / DDR4-SDRAM / LPDDR3-SDRAM
Maximum internal memory:16 / 32 / 8
Memory clock speed:1867 / 2400
Memory form factor:DIMM/SO-DIMM / On-board
Memory layout:1 x 8 / 2 x 4 / 2 x 8
Memory layout (slots x size):1 x 8 / 2 x 16 / 2 x 4 / 2 x 8 / 4 x 8
Memory slots:2 / 4
Memory slots type:SO-DIMM


Built-in camera:No / Y / Yes
TV tuner integrated: No


Bluetooth:Y / Yes
Bluetooth version:4.0 / 4.2
Ethernet LAN:Y / Yes
Ethernet LAN connection: Yes
Ethernet LAN data rates:10,100,1000
Wi-Fi:Y / Yes
Wi-Fi standards:802.11a, 802.11ac, 802.11b, 802.11g, 802.11n / 802.11a,802.11ac,802.11b,802.11g,802.11n / IEEE 802.11a, IEEE 802.11ac, IEEE 802.11b, IEEE 802.11g, IEEE 802.11n / IEEE 802.11a, IEEE 802.11ac, IEEE 802.11g, IEEE 802.11n / IEEE 802.11a,IEEE 802.11ac,IEEE 802.11b,IEEE 802.11g,IEEE 802.11n

Operational Conditions

Operating altitude:0 - 118110.2
Operating relative humidity (H-H):5 - 95
Operating relative humidity range:5 - 95
Operating temperature (T-T):10 - 35
Operating temperature range (T-T):10 - 35

Optical Drive

Optical Drive Type:N / No

Other Features

Display Diagonal (metric):21.5
Storage drive interface:SATA

Packaging Content

Bundled software:- iPhoto\n- iMovie\n- GarageBand\n- Pages\n- Numbers\n- Keynote\n- iBooks\n- Safari\n- FaceTime\n- Time Machine\n- Photo Booth\n- iTunes\n- Game Center / - Photos\n- iMovie\n- GarageBand\n- Pages\n- Numbers\n- Keynote\n- Safari\n- Mail\n- Messages\n- FaceTime\n- Calendar\n- Notes\n- App Store\n- iTunes\n- iBooks\n- Maps\n- Contacts\n- Reminders / Fotos\niMovie\nGarageBand\nPages\nNumbers\nKeynote\nSafari\nMail\nFaceTime\nMac App Store\niTunes\niBooks / iMovie\nGarageBand\nSafari\nFaceTime\nApp Store\niTunes\niBooks / iPhoto\niMovie\nGarageBand\nPages\nNumbers\nKeynote\niBooks\nSafari\nFaceTime\nTime Machine\nPhoto Booth\niTunes\nGame Center / iPhoto\nMovie\nGarageBand\nPages\nNumbers\nKeynote\niBooks\nSafari\nFaceTime\nTime Machine\nPhoto Booth\niTunes\nGame Center
Cables included:Lightning
Keyboard supplied:Y / Yes
Mouse included:N / No / Y / Yes
Power cord included:No / Y / Yes
Trackpad included:Y / Yes
Warranty card:Y / Yes


Product type:All-in-One PC / PC

Ports & interfaces

Combo headphone/mic port:Y / Yes
DC-in jack: Yes
DVI port:N / No
Ethernet LAN (RJ-45) ports:1
Ethernet LAN (RJ-45) ports quantity:1
Headphone outputs:1
Microphone in:N
Mini DisplayPort/Thunderbolt combo port:Y / Yes
Thunderbolt 2 ports quantity:2
Thunderbolt 3 ports quantity:2
USB 3.0 (3.1 Gen 1) Type-A ports quantity:4


AC adapter frequency:50/60
AC adapter input voltage:100 - 240
Autonomy mode:N / No / Yes


Bus type:DMI2
Conflict Free processor:Y
ECC supported by processor:N
Integrated 4G WiMAX:N
Maximum internal memory supported by processor:32
Maximum number of PCI Express lanes:16
Memory bandwidth supported by processor (max):29.86
Memory channels supported by processor:Dual
Memory clock speeds supported by processor:1333,1600,1866 / 1866,1333,1600
Memory types supported by processor:DDR3L-SDRAM
Memory voltage supported by processor:1.5
PCI Express configurations:1x16,1x8+2x4,2x8 / 2x8, 1x8+2x4, 1x16
PCI Express slots version:3.0
Processor boost frequency:3.5 / 3.6 / 3.8 / 3.9 / 4.2
Processor cache:4 / 6
Processor cache type:L3
Processor code:SR2AJ / SR2AL
Processor codename:Broadwell
Processor cores:4
Processor family:5th gen Intel® Core™ i5 / 5th gen Intel® Core™ i7 / 7th gen Intel® Core™ i5 / 7th gen Intel® Core™ i7 / Intel Core i5-5xxx / Intel Core i5-xxx / Intel Core i7-5xxx / Intel Core i7-xxx
Processor frequency:3.1 / 3.3 / 3.4 / 3.6
Processor lithography:14
Processor model:i5-5675R / i7-5775R
Processor operating modes:32-bit, 64-bit / 64-bit
Processor socket:BGA1364
Processor threads:4 / 8
System bus data transfer rate:5
System bus rate:5
Thermal Design Power (TDP):65

Processor special features

CPU configuration (max):1
Embedded options available:N / No
Enhanced Intel SpeedStep Technology:Y / Yes
Execute Disable Bit:Y / Yes
Graphics & IMC lithography:14
Idle States:Y / Yes
Intel 64:Y / Yes
Intel AES New Instructions: Yes
Intel Anti-Theft Technology: Yes
Intel Clear Video HD Technology: Yes
Intel Clear Video Technology:Y
Intel Clear Video Technology for MID: Yes
Intel Enhanced Halt State:Y / Yes
Intel FDI Technology:Y / Yes
Intel Secure Key Technology version:1.00
Intel Small Business Advantage (SBA) version:0.00
Intel Smart Cache: Yes
Intel Stable Image Platform Program (SIPP):N
Intel Stable Image Platform Program (SIPP) version:0.00
Intel Trusted Execution Technology:N / No
Intel TSX-NI:Y
Intel TSX-NI version:1.00
Intel Turbo Boost Technology: Yes
Intel Virtualization Technology (VT-x):Y
Intel Virtualization Technology for Directed I/O (VT-d):Y
Intel vPro Technology: No
Intel VT-x with Extended Page Tables (EPT):Y / Yes
Intel Wireless Display (WiDi) Technology: Yes
Intel® AES New Instructions (Intel® AES-NI):Y
Intel® Anti-Theft Technology (Intel® AT):Y
Intel® Clear Video HD Technology (Intel® CVT HD):Y
Intel® Clear Video Technology for Mobile Internet Devices (Intel CVT for MID):Y
Intel® Hyper Threading Technology (Intel® HT Technology):Y
Intel® Insider™:Y / Yes
Intel® InTru™ 3D Technology:Y / Yes
Intel® Iris™ Pro Graphics: Yes
Intel® OS Guard:Y
Intel® Quick Sync Video Technology:Y / Yes
Intel® Secure Key:Y
Intel® Small Business Advantage (Intel® SBA):N
Intel® Smart Cache:Y
Intel® Turbo Boost Technology:2.0 / Y / Yes
Intel® vPro™ Technology:N
Intel® Wireless Display (Intel® WiDi):Y
InTru™ 3D Technology: Yes
Processor ARK ID:87715 / 87718
Processor code:SR2AJ
Processor package size:37.5
Supported instruction sets:SSE4.1, AVX 2.0, SSE4.2 / SSE4.1,SSE4.2,AVX 2.0
Thermal Monitoring Technologies:Y / Yes
Thermal solution specification:PCA 2013D / PCG 2013D


Bundled software:iPhoto\niMovie\nGarageBand\nPages\nNumbers\nKeynote\niBooks\nSafari\nFaceTime\nTime Machine\nPhoto Booth\niTunes\nGame Center
Operating system installed:Mac OS X 10.11 El Capitan / macOS Sierra 10.12
Operating System Language:English / French / German


Card reader integrated:Y / Yes
Compatible memory cards:SDXC
Hard disk rotational speed:5400
Hard Drive Capacity:1000
Hard Drive Interface:SATA / Serial ATA
Hard drive speed:5400
Host interface:SATA
Number of hard drives installed:1
Number of SSDs installed:1
Number of storage drives installed:1
Solid-state drive capacity:256 / 512
Storage media:Flash / Fusion Drive / HDD / SSD
Total Storage Capacity:1000 / 2000 / 256 / 512

Weight & Dimensions

Depth:6.89 / 7.99
Depth (without stand):2.6
Height:17.7 / 20.3
Height (without stand):14.9
Weight:0.2 / 12.5 / 21
Width:20.8 / 25.6
Width (without stand):20.8