Zen 3

Zen 3 is the codename for a CPU microarchitecture by AMD, released on November 5, 2020. It is the successor to Zen 2 and uses TSMC's 7 nm process for the chiplets and GlobalFoundries's 14 nm process for the I/O die on the server chips and 12 nm for desktop chips. Zen 3 powers Ryzen 5000 mainstream desktop processors (codenamed "Vermeer") and Epyc server processors (codenamed "Milan"). Zen 3 is supported on motherboards with 500 series chipsets; 400 series boards also saw support on select B450 / X470 motherboards with certain BIOSes. Zen 3 is the last microarchitecture before AMD switched to DDR5 memory and new sockets, which are AM5 for the desktop "Ryzen" chips alongside SP5 and SP6 for the EPYC server platform. According to AMD, Zen 3 has a 19% higher instructions per cycle (IPC) on average than Zen 2. On April 1, 2022, AMD released the new Ryzen 6000 series for the laptop, using an improved Zen 3+ architecture. On April 20, 2022, AMD also released the Ryzen 7 5800X3D desktop processor, which increases the single threading performance by another 15% in gaming by using, for the first time in a PC product, 3D vertically stacked L3 cache. Zen 3 is a significant incremental improvement over its predecessors, with an IPC increase of 19%, and being capable of reaching higher clock speeds. Like Zen 2, Zen 3 is composed of up to 2 core complex dies (CCD) along with a separate IO die containing the I/O components. A Zen 3 CCD is composed of a single core complex (CCX) containing 8 CPU cores and 32 MB of shared L3 cache, this is in contrast to Zen 2 where each CCD is composed of 2 CCX, each containing 4 cores each as well as 16 MB of L3 cache. The new configuration allows all 8 cores of the CCX to directly communicate with each other and the L3 Cache instead of having to use the IO die through the Infinity Fabric. Zen 3 (along with AMD's RDNA2 GPUs) were also the first implementation of Resizable BAR, an optional feature introduced in PCIe 2.0, that was branded as Smart Access Memory (SAM).