DDR4 vs LPDDR4x RAM: What’s the difference?

You might have come across the term LPDDR4x or LPDDR5 RAM while browsing the specification of a Smartphone or a Laptop.

So what exactly is LPDDR Memories and how do they differ from traditional DDR memories?

Let’s find out.

There have been numerous groundbreaking innovations in the field of computer memories. We now have cutting edge technologies such as HBM (High-Bandwidth Memory), GDDR, and LPDDR.

While DDR Memory is an excellent choice for High-Performance devices like PCs, Workstations, and High-end Laptops, it isn’t ultra-efficient for mobile devices such as Smartphones, Tablets, and Ultrabooks.

That’s where LPDDR Memory comes into the picture. LPDDR stands for Low Power Double Data Rate and it is specifically designed for mobile devices.

It compromises a little on the operation speed in order to save some power. LPDDR4x is currently the most widely used LPDDR Memory while LPDDR5 is only supported on high-end smartphones SOCs like Exynos 990 and Snapdragon 865/865+.

In the Laptop segment, AMD and Intel are expected to support LPDDR5 Memory sometime in late 2021 or early 2022.

Let’s take a deep dive and learn the differences between the two.

    Types of DDR memories

There are three types of DDR memories available to consumers. They are:

  1. Standard DDR 
  2. Mobile DDR (LPDDR)
  3. Graphics DDR (GDDR)

As the name might already suggest, Standard DDR is a type of memory used in all desktop PCs, Laptops, and servers. This is the standard memory that is used in RAM sticks of most of the larger electronic devices.

Mobile DDR or LPDDR is a class of DDR memory found in smartphones, tablets, ultrabooks, embedded electronics, and other Internet of Things (IoT) devices. Since the devices in which LPDDR memory is found in devices that run on battery, the LPDDR memory must be optimized for offering good performance at low power. 

Interestingly, Laptops support both DDR and LPDDR as modern Intel & AMD CPUs have memory controllers for both DDR4 and the LPDDR4x on their chips.

While Laptop OEMs generally use DDR4 in High-Performance Laptops, LPDDR4x is a preferred choice for low-power ultrabooks.

In this article, we are going to keep our discussion limited to DDR and LPDDR memories. GDDR is something we should talk about in a different article.

But for those who are curious, just think of it as a memory that has high bandwidth and is optimized for the use of Graphics Cards. It is used for graphics-related applications like content creation and gaming. It is extensively used in Artificial Intelligence (AI) and Machine Learning (ML). 

    Generations of DDR Memories

The Synchronous Dynamic Random Access Memory was the original standard of all the RAM sticks that we use today. It was released in 1998. Subsequent releases of this RAM were named Double Data Rate or DDR owing to their doubled data transfer rate. 

DDR Memory transfers data on both the rising and falling edge of the clock signal and this is why it is given the name DDR (Double Data Rate)

DDR2 was released in 2003, and the DDR3 was released in 2007. The current standard was released in 2014 and is still powers most of the computers that we use today. DDR5 was released recently this year (2020).

DDR5 adoption will likely accelerate somewhere around Q1 2022.

Here is a table showing the data transfer rates and voltage levels of various generations of DDR memories. As you can see, the voltage levels have steadily reduced and the data transfer rates have increased.

Year of release Data transfer rate (MT/s) Voltage level (V)
DDR1 1998 266-400 2.5/2.6V
DDR2 2003 533-800 1.8V
DDR3 2007 1066-1600 1.35/1.5V
DDR4 2014 2133-3200 1.2V
DDR5 2020 3200-6400 1.1V

Note: It is possible to overclock DDR4  Memory way beyond 3200 MT/s.

Another table that shows the list of various generations of LPDDR memories is provided here. The generations of LPDDR memory have followed a similar pattern (like DDR memories) when it comes to improvements in the data transfer rates and voltage levels.

Year of release Data transfer rate (MT/s) Voltage level (V)
LPDDDR 2008 333-400 1.2V
LPDDR2 2010 800-1066 1.2V
LPDDR3 2012 1600-1866 1.2V
LPDDR4 2014 3200 1.1V
LPDDR4X 2017 3200-4267 0.6V
LPDDR5 2020 6400 0.5V
LPDDR5X 2023 (expected)

    Difference between DDR and LPDDR memories

In this section, we are going to talk about the differences between DDR and LPDDR memories.

Here are some of the parameters that differentiate both the memories:

  1. Performance
  2. Efficiency
  3. Price
  4. Upgradability

If you compare two similar laptops, one using a DDR memory and the other using an LPDDR memory, you won’t be able to notice the difference instantly. The difference comes in performance and battery life.

A laptop that uses a DDR memory is expected to run faster than it’s LPDDR counterpart in the benchmarks. But the LPDDR based laptop will be slightly more power-efficient.

The battery of a laptop with LPDDR memory would last longer than the one with DDR memory.

Samsung LPDDR4x Memory

Image Credits: Samsung

The price of regular DDR memories is also lower compared to LPDDR memories. The smaller size and higher efficiency increased the price of LPDDR memories.

Unlike the DDR laptops, the LPDDR4x laptops are not upgradable. The memory is directly soldered on the motherboard. This might be a deal-breaker for a lot of people who want a system with upgradeable memory.

The good thing about the DDR memories is that most of the DDR based laptops come with multiple memory slots and removable RAM. You can replace the older RAM stick with a newer one by yourself. 

    DDR4 vs. LPDDR4x and LPDDR4

Both the memories are omnipresent today on almost all the devices around us. The LPDDR4 RAM can hit clock speeds up to 3200 MHz just like the DDR4 RAM. The LPDDR4X RAM, however, offers improvements over the LPDDR4 RAM. 

The LPDDR4X RAM can hit clock speeds up to 4267 MHz which is impressive considering that it’s operating voltage is a lot lower compared to its predecessor.

DDR4 RAM works on 1.2V level whereas LPDDR4 RAM works on 1.1V. The LPDDR4X RAM can work on voltage level as low as 0.6V. This is a significant improvement.

    DDR5 and LPDDR5

As the computer peripherals like processors and GPUs keep getting a performance boost every year, there would come a time where they hit the bandwidth limits of current-gen DDR memory. Seven years is a long period. It’s time to say our goodbyes to the DDR4 memory sticks because, in the upcoming year or so, the fifth generation of DDR memories will take over.

DDR5 was recently announced. We can expect DDR5 memories to make their way to consumer devices soon enough. It’s just a matter of a year or two before we start seeing more and more devices with DDR5 RAM.




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