As we draw close to the launch of Ryzen 7000 series CPUs and accompanying AM5 motherboards (opens in new tab), enthusiasts start to turn their attention towards some of Zen 4’s as-yet-unrevealed characteristics. Questions on overclocking capabilities, cooling requirements, memory support, BIOS functionality, and general platform quirks are things that overclockers and hardware reviewers will be seeking answers to.
On a semi-related note, AMD has done a notable job at minimizing leaks despite the launch being a matter of weeks away. Unlike Intel’s 13th Gen chips, which have been benchmarked (opens in new tab) and overclocked (opens in new tab), many key details around Zen 4 remain unknown. One of the questions we have regarding Zen 4 regards its memory support, and WCCFTech (opens in new tab) (via Hot Hardware (opens in new tab)) has some information on just that.
Firstly, a little background. AMD’s memory system architecture is tied in with an internal interconnect it calls the Infinity Fabric. On AM4 DDR4 systems, the memory clock and Infinity Fabric clock are tied to each other in a 1:1 ratio up to a speed of 3,600MHz, or a bit more. But memory is Double Data Rate, so in the case of DDR4-3600, the memory clock and Infinity Fabric clock are 1,800MHz each.
You can set your memory faster than that, but doing so requires a 2:1 ratio, so if DDR4-3600 means the memory clock and IF clock are 1800Mhz to 1800Mhz, DDR4-4000 would equal 1000MHz to 2000MHz. The slower IF clocks means the system incurs a latency penalty which isn’t really overcome unless you move to very high-speed memory, which is expensive and not really worth it (opens in new tab).
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It seems as though the memory architecture of Zen 4 CPUs remains essentially the same, just tweaked to support DDR5.
According to WCCFTech, the Infinity Fabric can run at around 3,000MHz, which in a 1:1 ratio would mean that DDR5-6000 will become the new sweet spot. Much like with earlier Zen CPUs, you should be able to run faster memory, but then you’ll get a latency penalty because of the 2:1 memory to IF ratio.
Games tend to respond better to lower latency than they do to higher bandwidth. With that in mind, it’s looking like a good low latency DDR5-6000 kit could be the best way to extract the most from a Zen 4 system. Such kits are falling in price too, meaning fears of prohibitive DDR5 pricing slowing adoption of the AM5 platform are slowly fading.