AMD shows off Zen CPU
The first Zens to feature an octa-core consumer chip and a 32-core server chip, reports Gordon Mah Ung
AMD has unveiled its new Zen microarchitecture, with a pair of CPUs that could put the company back into the fight with Intel’s best (see our feature on page 80).
The firm said its Summit Ridge CPU, aimed at high-performance desktops, will pack eight cores and feature simultaneous multithreading technology to give it 16 threads of processing power. Summit Ridge is targeted for a Q1 2017 release, though a trickle of chips could appear sooner. A second chip for servers, codenamed Naples, will feature an astounding 32 cores with SMT, giving it 64 threads per CPU. SMT is similar to Intel’s Hyper-Threading technology, which splits a single core into two virtual cores for more performance.
This matters because up to now, some had speculated that Zen would fall short as recently-leaked benchmarks appeared to indicate it was no better than Intel’s two-year old Haswell microarchitecture. If other tests back up AMD’s demonstration, however, it appears to run neck and neck with the newly released Broadwell-E. If AMD can live up to its promise, it’s great news for the company as well as for consumers.
Clock-for-clock, it’s looking fast
The demonstration used the multithreaded Blender rendering application on two similarly configured PCs. One featured an engineering sample Summit Ridge chip, while the other had a new Intel Broadwell-E Core i7-6900K CPU – the latter can run up to 4GHz on some workloads. AMD conducted the test with both CPUs locked at 3GHz.
This methodology may seem unorthodox to some, but matching the chips clockfor-clock revealed their efficiencies. It also allowed AMD to protect the final shipping clock speeds of the chips. In the demonstration, which was performed just once, the Zen finished a nose ahead of the Broadwell-E Core i7-6900K chip.
It’s just one test on an unreleased CPU, and under the control of AMD, but the significance of the performance feat quells any fears that Zen would be the all-toofamiliar ‘too little, too late’ story from a company that has eaten Intel’s dust.
The demonstration exceeded the crowd’s expectations. “This is the most exciting AMD (CPU) launch in a decade,” enthused Kevin Krewell, principal analyst with Tirias Research, who attended the event. “They really have hit the mark on this.”
Performance and efficiency
AMD officials also lifted the curtain on Zen’s completely new microarchitecture. Gone are the shared, clustered multithread cores of the previous Bulldozer and Piledriver designs – Zen’s cores are standalone cores with SMT. The chip is being built by spin-off company Global Foundries on a 14nm process, using FinFet technology.
AMD CTO Mark Papermaster said the Zen core is about performance, throughput and efficiency. He revealed that it features a new high-performance cache, a greatly improved prefetcher and a completely redesigned branch prediction unit.
This is a big deal for AMD and the CTO showed it. “It’s a thrill to tell you we fully validated our performance achievement,” he said. Papermaster also promised that AMD was just warming up. “We are back. I told you a year ago we are back. And I’m very happy to tell you we delivered that performance and the team is not stopping, they are full forward on the next-generation design.”
The Summit Ridge chips are actually SoCs and will support DDR4, USB 3.1 10Gb/s, NVMe, SATA Express and PCIe 3.0. Other details of Summit Ridge such as die size, transistor count and thermals weren’t released at AMD’s event.
Naples brings 32 cores and 128 threads
It’s not just about the desktop, either. The chipmaker also wowed the crowd by demonstrating its server-oriented Naples SoC running in a dual-processor system. With each chip packing 32 cores and SMT, a Naples-based server would feature 128 threads of compute power.
Officials said Zen will continue to evolve – the new chip design will scale down to laptops sometime next year, though AMD first needs to ship the chips.
The consumer-focused Summit Ridge is expected to hit shelves in the first quarter of 2017, but AMD officials said some may ship in systems as soon as the end of this year. The server-oriented Naples chip would hit in the first half of 2017.
“I told you the best is yet to come,” enthused AMD CEO Lisa Su. “The next 12 months will be even more exciting.”
AMD’s Summit Ridge SoC (left) running at 3GHz can run a Blender render just as fast as a Core i76900K (right) running at 3GHz