AMD Ryzen 7000 users are in for a treat with the latest AMD Generic Encapsulated Software Architecture (AGESA) firmware. The update is seemingly making it possible to overclock DDR5 kits on Zen 4 systems up to around 8000 MT/s, something which was almost unthinkable even up until the prior AGESA release.
First noticed by hardware enthusiast and Twitter user Buildzoid, and later by other users, it looks like AMD Ryzen 7000, which struggled to go beyond 6400MT/s, is now comfortable reaching close to or even exceeding 8000 sometimes. The feat is made possible with AGESA 1.0.0.7B firmware version, though it is still not 100% recommended that all users try to run their RAM kits at 8000 as it is still a bit finicky at such speeds. However, DDR5-7200 or so could be easily doable now, it seems.
Buildzoid notes that their Ryzen 7900X PC achieved DDR5-8000 on a $300 eight-layered, Daisy Chain board, which generally is far inferior to ones sporting T-topology, in terms of memory compatibility, especially in scenarios where a user is running four sticks of RAM on a dual channel board (two DIMMs per channel):
Ryzen 7000. Running DDR5-8000. On a sub 300USD 8 layer daisy chain motherboard. This new BIOS is completely insanen. I might get DDR5-8000 stable on Ryzen before I ever get it stable on intel LOL.
Another Twitter user Chi11edog also posted screenshots of an X670E Ryzen 7950X system hitting 8200MT/s on a DDR5-7600 kit. They say:
A screenshot reveals MSI X670E Ace reaches DDR5-8200 with new BIOS. The RAM reaching DDR5-8200 is an OLOy Hynix A-die DDR5-7600 kit.
However, one thing noteworthy here is that DDR5 memory, past 6000MT/s (3000MHz) on Zen 4, operates in its Gear 2 mode, which AMD refers to as the "UCLK DIV1" mode. In this mode, the UCLK or the Integrated Memory Controller (IMC) clock runs at half the speed of the system memory (MEMCLK). Or in other words, the UCLK: MEMCLK ratio is 1:2.
This can be clearly observed in both situations above, where the Uncore frequencies (UCLK) are half that of the MEMCLK (Dram frequency). So performance can actually be worse on Ryzen 7000 once we move past 3000MHz (DDR5-6000). Robert Hallock, who served AMD as its Technical Marketing manager, stated that the Infinity Fabric clock (FCLK) on Ryzen 7000 is 1733MHz, though, they had recommended users keep the FCLK at Auto and maintain the 1:1 ratio between the UCLK and the MEMCLK (via Bionic_Squash on Twitter) for the optimum performance.
While such high speeds may not yield linear performance gains on the compute side of things, the story is different for the integrated graphics, which really only cares about the MEMCLK first and foremost. This is because the integrated graphics uses the system memory as its VRAM and hence these higher frequencies will lead to higher memory bandwidth, which is absolutely crucial to feed the on-board RDNA 2 or RDNA 3 graphics.