2 Sticks vs 4 Sticks of RAM: Which Is Best?

On the surface, this looks like a fairly straightforward question. But explaining why a two-stick kit is often the best choice takes a little unpacking, and spoilers: It’s going to be one of those annoying answers where it changes depending on your particular platform, the specifics of your processor and motherboard, which applications you’re using, and whether Venus is ascending. (That last one’s probably nonsense. Probably.)

Let’s start with the basics: your memory physically slots into your motherboard, which has traces that electrically connect that memory to the memory controller inside your processor. It’s this memory controller that dictates what you can and can’t do when it comes to all things memory related. From optimal memory configurations and performance through to what memory standard is supported, DDR4 or DDR5 say, how many channels you have on offer, how many ranks are supported, to how many sticks of memory can be accessed.

Your motherboard also has an important role in all of this, as it can offer fewer memory slots than those supported by the CPU. As ever when in the market for memory, either as an upgrade or for a new build, you should check your motherboard’s support pages for the memory QVL, which lists which memory kits have been tested with your particular motherboard. Ideally, you want a memory kit that appears on your motherboard’s QVL so that you know for sure that it should work at a given speed.

Before we get into the nuts and bolts, let’s cover a few terms you’ll come across when looking at memory and CPUs.

The number of channels your CPU supports dictates how many RAM modules can be accessed simultaneously. Most modern CPUs support dual-channel memory, and that’s what you’ll want to focus on. Even so, some high-end chips, like AMD’s Threadripper, support quad-channel setups, so if that’s what you’ve got, keep that in mind.

Your CPU connects to your memory using a 64-bit bus. Each memory chip on a memory module has either a 4-bit, 8-bit, or 16-bit bus. You need enough of these chips to make up a total 64-bit bus, or a single rank, so you’re looking at 4x 16-bit chips, 8x 8-bit chips, or 16x 4-bit chips. As you might expect, dual-rank RAM has two independent 64-bit buses' worth of memory chips. It’s worth noting that these two 64-bit buses are not accessed at the same time, but rather using an interleaved mode.

There’s essentially room for eight memory chips on each side of the memory module PCB, with space for a ninth if it is ECC memory. This can lead to memory chips being placed on both sides of the PCB yet still only be a single-rank module. This is why looking at both sides of the module is not, on its own, a good enough indicator of whether a given memory module is single or dual rank.

Stands for Error Correction Code and covers a type of memory that includes error correction. This needs to be supported by the CPU, motherboard, and memory to work. It’s generally essential in critical systems, such as servers and workstations, but much rarer on desktop.

Now all that’s out of the way, let’s look at some specifics of a modern CPU, namely the AMD Ryzen 7 9800X3D. This is a high-end CPU, but it’s a good representation of what’s available right now and what is offered by an up-to-date memory controller:

There’s nothing too surprising here for a modern CPU, other than the maximum speeds being very much on the conservative side. DDR5-6000 is the sweet spot for performance and compatibility right now, especially for an AMD CPU. The big takeaway is that you’ll achieve much higher maximum speeds going with a dual-module kit over a quad kit. Whether that’s single or dual rank doesn’t matter.

These numbers are backed up by enthusiast memory kits, which you’ll often find have just two modules but are rated for far higher speeds. For example, the likes of this 32GB VENGEANCE DDR5-6000 kit offers tight latencies for speedy operation, ideal for use in a gaming machine.

Kits with four memory modules are generally the best option for higher capacities. If you’re handling large data sets that you want to hold in memory, then a quad-module kit is a great option, something like this 96 GB VENGEANCE RGB 4x 24GB Kit.

One of the advantages of DDR5 is that it offers higher capacities than its predecessor, DDR4, which is why the default configuration has shifted from 16 GB (2x 8 GB modules) to 32 GB (2x 16 GB modules). 64 GB (2x 32 GB) is becoming more commonplace these days too, and the introduction of so-called non-binary memory kits, available as 24 GB and 48 GB modules, means you can hit up to 96 GB with just two sticks of RAM, or 192 GB if you want to go all out.

When you’re looking for a memory upgrade, you’ll want to pick the best kit for your needs, whether that’s performance or overall capacity. Then, if an upgrade is required at a later date, replace the kit with a new, validated kit that better suits your needs at the time of the upgrade, rather than mixing and matching different kits of memory (doing so may result in system instability).

If you need assistance finding the best compatible kit of memory for your system, check out the CORSAIR Memory Finder, which gives you recommendations based on your specific motherboard or system.