AMD Ryzen 9 3900X

As AMD’s third-generation Ryzen vies for the CPU throne, Jarred Walton goes all Zen 2 on us.

- Jarred Walton

The build-up to AMD’s launch party for its Ryzen 3000 CPUs – aka third-generation Ryzen, aka Zen 2 – has been huge, and the Ryzen 3000 processors are the first mainstream CPUs to utilize a 7nm manufacturing process. After flirting with the crown for the first two Ryzen generations, this could be the day when AMD claims an outright victory. But how has it managed this feat?

Zen 2 adds an improved L2 TAGE branch predictor, has a larger microop cache, doubles the maximum size of the L3 cache to 32MB per CCX and doubles the AVX floating-point performance. There’s also a third address-generation unit, larger buffers (reorder buffer, integer scheduler, physical register file, entry store queue and more), multiplication latency is reduced to three cycles from four and there are wider buses (256-bit instead of 128-bit) to improve bandwidth. PCIe Gen4 support is included, along with changes to the Infinity Fabric that links everything together, and there are improvements in memory compatibility.

Wrap all of that up in a 7nm bow, then move the memory controller out of the main CPU chiplet and into a secondary IO chiplet, and stick both into a single package – with the option to have dual-CPU chiplets on higher-tier models. That’s the Ryzen 3000 family. Currently it has everything from six-core/12-thread models like the Ryzen 5 3600 that uses a single CPU chiplet with two CCXes, up to the current king of the hill: the Ryzen 9 3900X, with 12 cores and 24 threads spread out over two CPU chiplets. The Ryzen 9 3950X will be a 16-core/32-thread solution. Phew!

But how does third-gen Ryzen perform? AMD has been more than willing to sell users more cores and threads at lower prices than Intel, and that in turn has forced Intel to step up from four-core/eight-thread mainstream CPUs such as the i7-7700K and finally start offering six-core/12-thread and eight-core/16-thread models without forcing users onto the X299 platform.