DDR4 or DDR5, what's the difference and how to choose for your 12th gen Alder Lake PC

ddr4 vs ddr5 for Intel Alder Lake

Intel's latest 12th gen Alder Lake micro-architecture is exciting for enthusiasts. Irrespective of its performance against its predecessors or AMD's competing Ryzen CPUs, the new generation of Intel processors is landing with a fundamentally new design that has not been seen before in the x86 space. The architecture is introducing the big.LITTLE approach (Intel calls it Big-Bigger), which is an extremely popular way of designing mobile phone SoCs where larger more powerful cores are combined with smaller more efficient ones to get the optimal performance out of a microprocessor.

Not just that, the Alder Lake also brings cutting-edge next-gen features that include PCIe Gen 5 and DDR5 / LPDDR5 memory support. Essentially Alder Lake's integrated memory controller (IMC) is ready for the fifth generation of double data rate (DDR) SDRAM but it is also compatible with last-gen DDR4 as well. As default spec, Intel states that the Alder Lake-S desktop CPUs would work with DDR5-4800 and DDR4-3200, but higher speeds should work fine too.

Although both DDR4 and DDR5 memory standards have the same 288 pin count, the pinout and keying are different which means the 600-series chipset-based motherboards accompanying Alder Lake-S, will come in two flavors as motherboard vendors will offer both DDR5 and DDR4 variants. Hence, folks looking to build an Alder Lake-S system will have to choose one over the other. To help distinguish, the DDR4 boards are labeled as such. Here are a few examples of Z690 boards both DDR4 and DDR5:

In this article, we lay down the benefits of each of the two platforms and hope to help readers best decide what's right for their next Alder Lake-S PC.

We start off with DDR5, which is the latest and greatest offering in the case of desktop DRAM and go through some of the new features and advantages it has to offer:

More speed = more performance, but not always

The most obvious advantage for having DDR5 memory over DDR4 is the higher speed and the additional memory bandwidth which will be on offer. This means that choosing DDR5 memory will be especially beneficial to workloads that are bandwidth-sensitive. Such workloads include:

Gaming using integrated graphics,
File compression,
Code Compilation,
Video transcoding/conversion,
Photo editing.

These tasks are generally much more susceptive to RAM speed and bandwidth over CAS latencies (CL). Hence, if you use your PC for running some of these applications, you should be better off with a DDR5 kit than using DDR4, even though the CL on DDR5 is much higher (Note that CL is only comparable when the RAM speed or frequency between two kits is roughly similar). It also makes more sense financially to buy DDR5 memory since a high-speed DDR4 kit, say DDR4-4400, seems almost twice as expensive as a DDR5-4800 option.

Additionally, if you buy a well-made DDR5-based Z690 motherboard now, you may in the future be able to upgrade to an even faster memory if you wanted. Something like ADATA's 12,600MT/s kit that's planned for launch later may also be a feasible option. All you'd need is a firmware update.

Fancier, more customizable RGB lighting

A gaming PC loses its charm without some RGB lighting. If you're a gamer who agrees, there's good news for you. DDR5 apparently comes with an upgraded serial presence detect (SPD) that will now allow for a more fine-tuned customization of the RGB lighting using the manufacturer-provided software.

Individually addressable RGB lighting on DDR5

New error checking capabilities

DDR5 introduces on-die error correction code (ECC) which was only limited to enterprise and server-class products previously. This will help correct single-bit errors or bit-flips and prevent data corruption that should lead to a more reliable platform overall.

On-DIMM power management

In the case of DDR5 memory, the power management integrated circuits (PMICs) have been moved on to the DIMM itself which were previously on the motherboard. This combined with the upgraded SPD Hub should allow for greater control and regulation of power, voltage, and current flow.

With all these advantages in favor of DDR5, you may be wondering, is there any reason at all to look back at a DDR4 option for Alder Lake-S? The answer is yes.

DDR4 is cheap and readily available

The biggest benefit, at least for the short term, is the price of DDR4 memory. MSI recently stated that it was expecting the initial few batches of the new DDR5 products to be expensive, which is natural for any newly launched product. However, due to all the additional on-die features of DDR5 like PMIC and ECC, that we talked about earlier, the cost of manufacturing the DDR5 modules is also significantly higher than previous generation products. And we can't forget that the price of a Z690 board isn't going to be cheap either.

DDR5 does not always equal faster

Although RAM speeds are important for some workloads, there are many other tasks that are barely affected at all by higher-speed memory. For example, rendering and video editing are amongst some of the applications least affected by DRAM speed and bandwidth, even though they tend to eat up lots of memory space. Gaming using a dedicated discrete GPU at higher resolutions is also something that shouldn't see any performance loss if you'd decide to opt for a DDR4 system.

DDR4 = easy stopgap upgrade path to Alder Lake

DDR4, unlike DDR5, is backward compatible with previous-gen Intel processor families and sockets like LGA1200 (Intel 10th and 11th gen), LGA1151 (Intel 8th and 9th gen), as well as AMD's AM4. So if you're already on such a system that sports a top-notch, premium DDR4 kit, you can re-use that memory on a new Alder Lake-S system, provided that the DDR4 memory doesn't hinder your performance.

Likewise, you could also upgrade just your DDR4 memory for now - which will act as a stopgap or a bridge - so that the rest of the rig can be upgraded to a new LGA1700 socket-based Alder Lake-S system later. Additionally, if Intel continues with its two generations per socket trend, then the 13th gen Core processors, purportedly Raptor Lake-S, could potentially also end up on your upgrade menu.

To sum it up, DDR5 is new and exciting with lots of cool new features. The fifth-gen DRAM standard brings to the table much more than just higher speeds, unlike DDR4. An enthusiast would be enticed to purchase the platform and that's awesome. However, as we pointed out above, there can be genuine reasons to opt for a DDR4 motherboard too.

Ultimately, there is no absolutely right or wrong choice here and the decision should be based on the needs and the purpose around which that system is built for. To hopefully help you make that, we listed above some of the major pros of choosing one platform over another. But we may have missed some too that you can tell us all about, and more, in the comments below.