DDR3 vs DDR4 RAM: Key Differences Explained

DDR3 RAM had a long life after its release in 2007, powering mainstream laptops and desktop computers for years. However, DDR4 RAM was released to the public in 2014 and has since become the most common memory type in desktop PCs, laptops, and tablets. With major changes in physical design, specifications and features, motherboards with DDR4 slots cannot use DDR3 RAM and DDR4 RAM cannot be placed in a DDR3 slot. Neither is compatible with the newer DDR5 memory.


DDR4 tends to run at 1.2 volts by default, while DDR3 runs at 1.5V. While it may not seem like much, that’s a 20% improvement in efficiency between generations. For most home users, the difference in voltage ultimately results in lower power consumption and less heat build-up, which can be especially important with laptops where it can affect battery life.

DDR4 is not only more energy efficient, it is also a lot faster. DDR3 specifications range from 800 to 2,133 MTps (millions of transfers per second). In comparison, DDR4 RAM ranges from 2,133 to 3,200 MTps, not to mention the faster kits available through XMP and overclocking.

When you buy RAM, you can identify the speed by its name, e.g. Crucial Ballistix 16GB DDR4-3200. This indicates that it is DDR4 RAM at 3,200 MTps.

MTps vs MHz

To avoid confusion, it is worth clearing up the difference between MTps and MHz. Some companies advertise RAM in MTps and others in MHz.

MTps (millions of megatransfers per second) measure bus and channel speed based on effective cycles per second. MHz (megahertz per second) measures the transmission rate of a device in one million cycles per second.

Generally, DDR RAM is measured in MTps while SRAM (Static RAM) is measured in MHz as it cannot produce more than one operation per second. DDR3 RAM running at 1066.6 MHz will be presented as DDR3 2133. As DDR, or double data rate, RAM has two processes running at the same time, the 1066.6 MHz is doubled to equal 2133 MTps.

Essentially, MHz and MTps are the same, but it’s important to know how a manufacturer represents their measurements.

Is DDR4 faster than DDR3 RAM?

HyperX DDR4 memory modules.

DDR4 can and will run much faster than even the best DDR3, but there is some crossover.

In terms of transfer speed, DDR4 is capable of a higher million transfers per second. However, MTps is not the only specification to consider when purchasing RAM.

Timings, such as Column Access Strobe latency (CL), also play an important role in overall memory performance. CL determines the number of clock cycles that RAM needs to provide the data requested by the CPU.

To put it in context, high clock speeds don’t necessarily mean faster RAM. High latency can lower the results slightly, so it’s worth comparing all the specs to find the right type of RAM for your requirements.

By comparing Corsair’s Vengeance DDR3 kits to their Vengeance LPX DDR4 kits, there is a distinct difference in performance and speed.

a comparison of Corsair's ddr3 vs ddr4 read and write performance

While the read/write speeds are marginally slower on their DDR4 kits compared to DDR3 at 2133MHz, it’s important to remember that this is the entry-level speed for DDR4.

a comparison of corsair's ddr3 vs ddr4 ram in latency testing

In terms of latency, DDR3-1600 has higher latency than any DDR4 kit. At 2133MHz, the DDR4 kit is slightly higher than DDR3-2133, but as the memory clock speed increases, the overall latency decreases, even if the timing is looser.

Ultimately, DDR4 is faster than DDR3 RAM. It also offers more performance at a lower cost per dollar compared to any DDR3 RAM except at the entry-level 1,600MHz.

High Frequency DDR4 RAM

High-frequency DDR4 RAM like the Corsair Vengeance LPX 16GB is capable of reaching speeds of up to 4,000 MHz. Gamers looking to push their machines to get the best performance can overclock their RAM for demanding systems.

However, manufacturers like HyperX have pushed the boundaries even further with their HyperX Predator DDR4 family of RAM, which is available between 2.666 Mhz to 5.333 Mhz.

In April, they even set the world overclocking record of 7,200MHz with their HyperX Predator DDR4 memory.

Why DDR3 and DDR4 don’t work together?

High Quality DDR3 ECC Computer Memory

One of the main differences between DDR3 and DDR4 RAM is the layout of the physical pins. DDR3 RAM uses a 240-pin connector, while DDR4 uses a 288-pin connector. A motherboard with DDR4 compatibility will not work with DDR3 RAM and vice versa. The connector pins are different so you can’t accidentally install the wrong type of RAM.

The different voltage requirements also mean that a system designed with DDR4 in mind would not supply the correct voltage for DDR3 by default and may not even have been designed with that voltage capability in mind.

The difference between DD4 and DDR3 prices

When DDR4 first hit the market, the price difference was significant. However, with more compatible motherboards and CPUs, DDR4 RAM has come down in price.

But compared to DDR3, DDR4 RAM is often more expensive. It’s not a huge difference, especially if you buy a few modules. However, if you need a large amount of RAM, the cost can add up quite quickly.

What about DDR5 RAM?

DDR5 RAM was released in 2020 but has not yet made a significant impact on the market.

With the release of Intel’s Alder Lake CPUs, it would be safe to say that DDR5 will be more widely available in late 2021 and 2022.

DDR5 specifications start at 4,800 MHz and peak at 6,400 MHz, with the potential for higher clock speeds in the future.

Choosing the Right RAM

DDR3 vs DDR4 RAM comes down to the hardware in your system. If you’re using an older motherboard and CPU, your option is probably DDR3.

However, if you already have or are thinking of investing in a compatible motherboard and CPU, DDR4 RAM is a more future-proof choice.

It is slightly more expensive and in very few cases at lower clock speeds it may not be as fast as DDR3 RAM, but it is supported by the latest hardware.

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