AMD hasn’t formally announced that it has won the Xbox Next and PlayStation 5 contracts just yet, but it’s considered a more-or-less foregone conclusion in the industry. Now, noted hardware leaker TUM_APISAK has released a Tweet he claims identifies and unveils AMD’s Gonzalo APU — or at least, what its specifications claim about the chip.
— APISAK (@TUM_APISAK) January 18, 2019
Point of clarification. The CPU he compares with (ZD3601BAM 8 8 F4 _ 40/36 _Y is the engineering sample product number for a six-core Ryzen CPU that surfaced before Ryzen 2nd Generation had formally launched).
As the tweet illustrates, the combined implication of the data is for a chip with a 1.6GHz base clock, eight CPU cores, and 8MB of L3 cache. Bradd Sams, executive editor at Thurrott, has claimed that Microsoft’s Xbox Scarlett will use an AMD Zen 2 chip on the 7nm node, while the amount of L3 on this core (8MB) is closer to what Zen used. There are claims that the boost CPU clock will be as high as 3.2GHz.
As far as CPU architecture and process node are concerned, the question breaks down like this: 7nm seems incredibly likely, given that the node should be fully mature by then and Navi is debuting on that process. Whether the chip will use Zen+ or Zen 2 architecture is an interesting question. AMD could go the chiplet route here, or it might not.
Either way, the PS5 and Xbox Next will pack serious improvements in overall CPU performance. Remember, the CPU core inside of the Xbox One and PS4 is based on Jaguar, a 2013 low-power core from AMD intended for the mobile market. Kabini wasn’t a bad CPU core — I was rather fond of it, as far as the low-end of the PC market was concerned — but it was unquestionably a limited CPU core. Even its top-end mobile SKUs lagged behind AMD’s big-core hardware. Tests like Cinebench showed it could hang with Kaveri clock-for-clock, but the half-speed L2 cache and power-efficient focus made it a significantly weaker performer in other contexts.
When deployed in consoles, there were other weaknesses as well. The PS4 and Xbox One both deploy two quad-core clusters, each with its own L2. According to Naughty Dog, the L2 access latency across these clusters is almost as high as native DRAM access, thanks in part to the half-speed L2 cache. Bringing the L2 up to full speed should significantly improve performance, while building a unified eight-core block instead of a pair of quad-cores will improve multi-threading and the latency associated with shifting data between core clusters.
The low base clock speed isn’t particularly concerning. Recall that Ryzen is an estimated 1.52x faster than AMD’s previous Bulldozer architecture. The gap between Kabini and Kaveri was never that high — in Cinebench, at the same clock, the two were equal — but the overall performance difference between the two was often more a function of clock. Compared in Anandtech’s Bench and with the impact of clock speed removed, the AMD A10-7850K (Kaveri) was between 5 percent – 45 percent faster than Kabini (the same CPU inside the Xbox / PS4), with the gap often landing in the 1.1x – 1.25x range. Call it 1.25x to be polite, and the net gain from Kabini to Ryzen could easily be 1.8x or more.
Even if we assume a default 1.6GHz static clock with no Turbo mode whatsoever, at any point, switching from Kabini to Ryzen should be worth a huge performance improvement, dwarfing the gains from PS4 – PS4 Pro or Xbox One – Xbox One X. With an estimated peak turbo clock of 3.2GHz, it shouldn’t be any kind of problem for the new AMD APU to offer 2x the sustained performance of Jaguar, and that’s strictly based on things like L2 latency, cross-core communication latency, and general IPC. Any additional improvements gained from increased support for SIMD instruction sets would be ladled on top of that.
Now, how much will this increased CPU horsepower help improve game quality? That’s less clear. GPU horsepower has always been much more central to the overall performance equation than the CPU. But having more CPU cores aboard (and having hopefully better access to multi-threading resources) should give developers more legroom to improve AI and increase game multi-threading. There’s been a lot of emphasis on the PC side on improving game visuals through the adaption of HDR or FreeSync as opposed to strictly pushing detail levels, and it’d be nice to see game developers targeting something more along the lines of a locked 60fps at 1080p and a 30+ frame rate at 4K (If it has to be 30fps at 4K, I’d love to see locked 30, rather than what’s all-too-often a “Take a shot at 30fps and settle for 25fps”) kind of system.
CPU-wise, at least, the new consoles should be far more powerful than the last few generations. We’ll have to wait to see how much horsepower the GPU side of the equation will receive.