60,456 reviews

Apple iMac Retina 5K, 27-inch, Early 2019 - 4.6GHz Core i5 Compatible Memory / RAM Upgrades

100% Apple Compatible Upgrades from the UK's Leading Supplier of Memory & SSDs

Not your exact model? See all Apple iMac or 2019 First Released models, or use our Apple Serial Number Search

Model Specifications 220,342 Apple Upgrades Supplied

Make & Model:

Apple iMac Retina 5K, 27-inch, Early 2019 - 4.6GHz Core i5

Apple Reference:

iMac19,1 3194 A2115 MRR12LL/A

Total Memory Slots:

Maximum Memory:

Installed Memory:

Instantly check how much Memory you currently have installed

Important Notes:

Mr Memory recommends you install modules in pairs for Dual-channel performance - View Dual-channel Memory Video.

This iMac officially supports 64GB maximum (4 x 16GB).
Mr Memory has tested in-house and can confirm the unofficial maximum for this model is 128GB (4 x 32GB).

For Guaranteed Compatible Memory, please choose a model that matches your model's Release Date, Screen Size and Processor.
How to Identify your Apple.

Enhance the performance of all macOS versions
Optimise the speed and efficiency of every macOS release, including Tahoe, Sequoia, Sonoma, Ventura, Monterey, Big Sur, and more.

To get the best performance and speed from your iMac, upgrade to the maximum memory.

We always send brand new matched modules, when you order 2 or more.

Help Me Choose

DDR4 PC4-21300 2666MHz 260-pin SODIMM (2667MHz)

Product Specifications

Upgrade your computer with brand new DDR4 2666MHz memory - the quickest, easiest way to boost PC performance and speed! Adding extra memory is the most cost-effective way to make your operating system and applications run faster and smoother for peak performance.

Size

(Inc VAT)

32GB

1 DAY

£300.00 each

£306.00

Save £6.00 Today

ADD TO BASKET

16GB

IN STOCK

£112.80 each

£118.80

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ADD TO BASKET

8GB

IN STOCK

£66.00 each

£68.40

Save £2.40 Today

ADD TO BASKET

Benefits of Upgrading Installation Guides Returns & Refunds Delivery Options

Orders placed Monday to Friday after 4.30pm (UK time) or on weekends/bank holidays will be processed the next business day.
(subject to stock, order verification and chosen delivery option)

Next Day Delivery Available - See all delivery options on the basket page.

TRUSTED
Lifetime Warranty

100%
Compatible

FREE & FAST
UK Delivery

UNLIMITED
Support

32 YEARS
and Counting

Trusted & Reliable Customer Reviews

Good service

Great after care when we had an issue

Chris - Friday 22nd May 2026

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Mr Memory was very helpful all the time

M. Bran - Tuesday 19th May 2026

Verified order

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Items arrive quickly and well packaged

Items arrive quickly and well packaged. Bought from Mr Memory 4 or 5 times over past few years. Always great customer support.

Sharon E - Monday 4th May 2026

Verified order

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First Class all round!

I don't use Mr Memory frequently but have bought from them for many years when upgrading my (and extended friends and family's) various computers or replacing hard drives. I have never had cause to contact them outside of the normal process because a) everything has always been spot on and b) I haven't been a numpty before and ordered the wrong thing! So the most recent transaction with them has been a wholly enjoyable experience and totally different from any other contact I have had with any other company.
I ordered PC memory, when I should have ordered laptop memory -totally my fault! - and upon completing the returns details (which is all free post by the way!) I received an email from a wonderful person named Zoe, who happens to be Head of Operations, within 30 minutes giving me a return reference and asking what I wanted to exchange it for (the return request was for replacement not refund).
I replied with my brain fart issue and stated the laptop memory needed.
I received a very fast reply stating the laptop memory will not be in stock until the following Monday.
I then - being the awkward customer I am - asked if it could be posted to a different address as I was on a bit of a time crunch. Zoe replied saying it wouldn't be a problem. I then asked how I could pay the (very small amount) difference..... and she replied saying that they wouldn't charge any more than I had already paid!
If anyone out there doesn't agree about the absolute first class customer focus and service after hearing all my issues and stupidity that Zoe dealt with....
I have no words!
Thank you Zoe and Mr Memory, I am very glad I purchase hardware from you and will continue to do so!

HSP - Friday 24th April 2026

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4.9 out of 5 MORE REVIEWS

Benefits of Upgrading your Computer Memory

Upgrading is Easy - Go to the Maximum - Renew your Device

If you can change the batteries in your remote control, you can upgrade your memory too! It really is that simple!

The files and programmes on your device are stored on the Hard Drive or Solid State Drive, not the RAM - so you will not lose anything when replacing modules.

Speed & Peak Performance

Improve start-up time and optimise the speed of your operating system
Maximise all-round efficiency & multitask with ease
Speed up your games and apps, including video and photo editing software
Peak performance for home schooling, streamers, video callers, gamers & online shoppers
Improve the performance of your favourite video streaming platforms

Simple, Quick & Easy

Easy as 1, 2, 3 (Order, Deliver, Install)
Upgrading your computers memory is simple with our easy to follow installation guides & videos
Free support provided by our friendly specialists should you need help
Easy to install - Upgrade your computer in less than 5 minutes
Working from home? Ensure your computer is up to the task with a simple Memory upgrade

Big Savings

Don't waste money on a new machine when you can renew & extend what you have!
Save money on unnecessary installation costs by upgrading yourself
Increasing your computers memory will give you the biggest performance increase for your money
Save hours of lost time waiting for your computer to load
Maximise the value of your computer

Reduce your impact on the Environment

Join 500,000+ Mr Memory customers who saved their computer from a trip to the recycling centre
Renewing your device instead of replacing it reduces e-waste and greenhouse emissions
Help electronics become a more sustainable part of our lives by renewing them
By using your electronic devices for as long as possible, you are saving the planet’s resources
Return your old Memory to us and we will ensure it is responsibly recycled

Working from Home & Hybrid Working

If you work from home or are thinking of doing so in the future you need to have the right tools available to do your job as efficiently as possible. Whether you use your own computer or a company owned device, do not be slowed down by insufficient memory or storage. Upgrading the memory and/or SSD is a simple way to save time when working from home.

Increase home working efficiency and performance
Create a stress free and healthier environment with less distractions
Minimise the impact of a slow connection, and improve the responsiveness of video calls
Easily upgrade your computer at home, and claim on company expenses
Working from home has been shown to improve creativity and give a better home life/work balance
Save time and money on commuting, and benefit from flexible scheduling

Trust the Mr Memory Brand

Feel Safe, Feel Secure & Feel Appreciated

We help people to feel safe, happy and secure. You can trust the Mr Memory brand - we will protect your data, save you money and improve the performance of your valued devices, whilst being eco-responsible.

Our specialists provide free support to anyone who needs it - at any stage of the order process. Our communication is fast and our guidance is as technical or as basic as you need it to be.

Buy from a UK based company with 32 years experience
100% Safe & Secure website
Fully informed at every stage of the order
Fast dispatch - 98% of orders dispatched same day
Highest quality brand new products from the best brands in the world
RAM extensively tested prior to shipment
Accurate database with new models added daily
30-day credit available to the Public / Private Sector
250,000+ businesses use Mr Memory for their Memory/RAM & SSD upgrades
Over 150,000 registered online customers
We are compliant with the latest privacy regulations including the UK and EU GDPR

Working Towards a Sustainable Future

Mr Memory is tackling climate change as a team with an aim to being carbon neutral by 2027.

Our employees are encouraged to walk, cycle or car share
We encourage our employees to stay healthy, eat more sustainable food and buy locally
We always try to purchase from UK based companies where possible
We hold regular staff meetings where our employees opinions on climate change are heard
We supply appropriate uniform to reduce heating and air-con use
We have waste reduction procedures in place - all of our packaging can be recycled
Our refuse bags are bio-degradable
Our cleaning equipment and products are all eco-friendly
Our printing is limited to essential customer paperwork only
When not in use all electrical devices are turned off and we always purchase energy efficient devices
Our energy supplier is moving to 100% renewable electricity and is a COP29 Principal Partner
All of our suppliers use recyclable packaging, which we reuse where possible
We are constantly reviewing our Sustainability Statement

Play our educational HD videos

WATCH 30+ VIDEOS

Module:	x1 (single module only)
Memory Brand:	We supply the best brands in the world so you will only receive brand new premium memory of the highest quality
Compatibility:	100% Guaranteed Compatible with your Apple iMac and All Operating Systems
Product Warranty:	Full Lifetime Warranty
System Warranty:	This upgrade will not invalidate your system warranty
Speed:	2666MT/s (PC4-21300)
Technology:	DDR4 SDRAM
Pins:	260-pin, Gold Connectors
Form Factor:	SODIMM (Small Outline Dual Inline Memory Module)
Module Dimensions:	70mm x 31mm (LxH)
Data Integrity:	Non-ECC
Ranking:	1R, 2R, 4R
Voltage:	Low - 1.2V
CAS Latency:	You will receive memory with the correct CAS Latency for your model

Apple iMac Retina 5K, 27-inch, Early 2019 - 4.6GHz Core i5 Compatible Memory / RAM Upgrades

100% Apple Compatible Upgrades from the UK's Leading Supplier of Memory & SSDs

Example 1

Example 2

Product Specifications

Installation & Support

Installation is Easy with Fast & Professional Support

Installation

Support

Delivery, Returns & Refunds

Fast Delivery

Fast Returns & Refunds

Trusted & Reliable Customer Reviews

Good service

Mr Memory was very helpful all the time

Items arrive quickly and well packaged

First Class all round!

Benefits of Upgrading your Computer Memory

Upgrading is Easy - Go to the Maximum - Renew your Device

Speed & Peak Performance

Simple, Quick & Easy

Big Savings

Reduce your impact on the Environment

Working from Home & Hybrid Working

Trust the Mr Memory Brand

Feel Safe, Feel Secure & Feel Appreciated

Working Towards a Sustainable Future

We are eco‑responsible

Play our educational HD videos

What is a Matched Pair?