AMD Ryzen 3000 Zen 2 CPUs Reportedly Support Up To DDR4-5000 For Glorious Bandwidth

More details about AMD's forthcoming Ryzen 3000 series of desktop processors is starting to leak out ahead of a full reveal at Computex next month. If the latest bit of information posted to Twitter by one of AMD's partners is accurate, then the upcoming Zen 2 parts will support memory speeds of up to DDR4-5000MHz.

This latest revelation follows a previous leak that seemingly confirms AMD is planning to launch both 16-core and 12-core variants of its Zen 2 chips, in addition to the usual 8-core, 6-core, and 4-core suspects. Pairing 5000MHz memory modules with one of the top end parts is an interesting proposition for sure, especially if AMD delivers a significant bump in IPC (instructions per clock) performance—around 15 percent is what the going rumor points to.

According to Yuri Bubliy (@1usmus on Twitter), developer of the Ryzen DRAM Calculator, Ryzen 3000 series processors will be able to handle blistering fast 5000MHz memory, for those who can afford it (faster RAM kits carry a pricing premium).
"I think it's time to start. The maximum value of the frequency of RAM Zen 2 generation is 5000MHz mode UCLK == MEMCLK / 2," Bubliy wrote on Twitter.

What he's saying there is that the UClk on Ryzen 3000 series processors is equal to half of the memory module's speed. So for a kit of RAM that can cruise along at 5,000MHz, the UClk would be at 2,500MHz (1,250MHz effective).

UClk refers to the frequency of the Unified Memory Controller (UMC). To put this claimed speed into perspective, a first-generation Ryzen 7 1700 running at stock speeds has a 3,000MHz core clock with 2,400MT/s DRAM and a UClk of 1,200MHz (600MHz effective).

Ryzen Chiplet

One thing that is making this additional speed possible is AMD's new chiplet design. The memory controller is effectively separated from the CPU cores into a distinct I/O die. Note that the DRAM clock is also linked to AMD's Infinity Fabric—5,000MHz is an unrealistic expectation there, hence the half-divider mode that Bubliy refers to, for the UClk frequency.

This is an interesting development, though not all setups will be able to hit the max frequency supported. It will require some burly RAM, and a capable motherboard. And because this still falls into the realm of overclocking, experience and luck will both play into it.

Still, this could help AMD and its motherboard partners encourage users to upgrade to an X570 motherboard, even though previous chipsets based on socket AM4 will also support Ryzen 3000 series CPUs.