AMD Zen Quad-Core Unit Details Revealed

For some time, reports have circulated that AMD’s new Zen architecture will be composed of four CPU cores, often referred to as the “Zen Quad-core unit.” Now, a slide that emerged from AMD’s recent “performance reveal” has confirmed the news, referring to the collection of four subunits as the “CPU-Complex” (CCX) and revealing the L2 and L3 caches available to each core.

The CPU-Complex consists of four independent cores, each sharing an 8MB L3 cache, while each individual core has a dedicated 512KB L2 cache, making Zen differ from AMD’s Bulldozer architecture, which shared the total cache with adjacent cores.

“AMD will control core-counts by controlling CCX units. A “Summit Ridge” socket AM4 processor features two CCX units (making up eight cores in all), sharing a dual-channel DDR4 memory controller,” TechPowerUp reports (via Heise Online), “and the platform core-logic (chipset), complete with an integrated PCI-Express root complex. Socket AM4 APUs will feature one CCX unit, and an integrated GPU in place of the second CCX. With this, AMD is able to bring the two diverse desktop platforms under one socket.”

AMD is hoping that Zen will pose a real threat to Intel, which has dominated the CPU market for the last two decades.

“The performance and efficiency of our ‘Zen’ core showcases AMD at its best,” Dr. Lisa Su, CEO of AMD, said at the recent Zen event in San Fransciso. “Over the last four years we have made significant investments to develop a high-performance, multi-generation CPU roadmap that will power leadership products. Customer excitement for ‘Zen’ continues to grow as we make significant progress towards the launch of new products that will span from the datacenter to high-end PCs.”