As the Ryzen 7000 series CPUs and accompanying AM5 motherboards get closer to launch, (opens in new tab)enthusiasts are starting to turn their attention to some of Zen 4’s as-yet-undisclosed traits. and hardware reviewers want answers.
On a semi-related note, AMD has done a remarkable job of minimizing leaks even though it was only weeks away from launch. Unlike benchmarked Intel 13th generation chips. (opens in new tab) and overclock (opens in new tab), many of the important details about Zen 4 remain unknown. One of the questions about Zen 4 concerns its memory support. WCCF Tech (opens in new tab) (via hot hardware (opens in new tab)) has some information about it.
First, a little background. AMD’s memory system architecture is tied into an internal interconnect called the Infinity Fabric. In AM4 DDR4 systems, the memory clock and the Infinity fabric clock are correlated in a 1:1 ratio up to speeds of 3,600MHz or higher. However, the memory is double data rate, so for DDR4-3600, the memory clock and the Infinity Fabric clock are each 1,800MHz.
You can set memory faster than that, but this requires a 2:1 ratio. So if DDR4-3600 means memory clock and IF clock are 1800Mhz to 1800Mhz, DDR4-4000 equals 1000MHz to 2000MHz. A slower IF clock means the system incurs a delay penalty. This isn’t really overcome unless you move to very fast memory. This is expensive and not really worth it. (opens in new tab).
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It looks like the Zen 4 CPU’s memory architecture will remain basically the same, with some tweaks to support DDR5.
According to WCCFTech, Infinity Fabric can run at around 3,000MHz. This means that, with a 1:1 ratio, DDR5-6000 will be the new sweet spot. Like previous Zen CPUs, it should be able to run faster memory, but with a 2:1 memory to IF ratio, it comes at a latency penalty.
Games tend to respond better with low latency than with high bandwidth. With that in mind, a good low-latency DDR5-6000 kit looks like the perfect way to get the most out of your Zen 4 system. Prices for such kits have also fallen. In other words, concerns about exorbitant DDR5 prices slowing adoption of the AM5 platform are fading away.
