AMD’s Zen CPUs, code-named Summit Ridge, are set to arrive early next year, but there’s a lot of groundwork to be done before those next-generation processors make their entrance. Way back in January, AMD announced it would be unifying its desktop platforms for its CPUs and APUs with a new socket—AM4. Now, motherboards and chipsets with that new socket are on the move toward retail. Yesterday, the company announced that desktop AM4 motherboards and its seventh-generation desktop APUs, code-named Bristol Ridge, are now available for its OEM partners.
For some background, today’s AMD APUs require Socket FM2+ motherboards that are incompatible with their integrated-GPU-free CPU cousins, which still drop into Socket AM3+ motherboards. Each of those sockets has a range of associated chipsets, too, serving builders of all budgets. AM4 wipes away all of that cross-platform incompatibility with a single socket and motherboard lineup. Compatible APUs and CPUs will offer modern features like PCIe 3.0, DDR4 memory controllers, and support for NVMe storage devices on top of the new features that AM4-platform chipsets will include.
The first family of AM4 APUs, code-named Bristol Ridge—or “seventh-generation APUs,” as you’ll see them referred to in marketing materials—have been available in notebook PCs for a couple of months in TDPs ranging up to 45W. As a brief refresher, Bristol Ridge parts are built around AMD’s Excavator CPU core and GCN 3.0 graphics technology, but improved process technology and lots of optimization work have allowed those chips to deliver modest improvements in performance over Carrizo parts on the same 28-nm process. More importantly, Bristol Ridge parts give us our first glimpse at how AM4 motherboards might look for Zen CPUs when they arrive next year.
Back when Carrizo APUs arrived for notebooks, AMD brought that processor family’s Excavator CPU core to the desktop with just one part: the Athlon X4 845, a 65W quad-core CPU without integrated graphics. That Athlon ran at 3.5GHz base and 3.8GHz boost clocks. In contrast, Bristol Ridge is a family of desktop APUs with Radeon graphics onboard, although one Bristol Ridge CPU will also be available in the form of the Athlon X4 950.
The extensive tweaking and tuning in Bristol Ridge is perhaps most evident in the specs of the top-end A12-9800 APU. Despite its 65W TDP, this chip’s boost clock is only 100MHz short of the 4.2GHz the 95W A10-7890K can muster. The graphics processor on this chip also runs its 512 GCN stream processors considerably faster than the ones on the A10-7890K at their quickest: 1108MHz on the Bristol part versus 866MHz on the Godavari chip.
Combined with the architectural improvements of the Excavator CPU cores over the Steamroller cores in the A10-7890K, the A12-9800 might be as fast as or faster than the Godavari part in practice (though it doesn’t have that K chip’s unlocked multiplier for easy overclocking).
AMD wanted to make it clear which of its seventh-generation APUs are lower-TDP parts, as well, so it’s bringing back the “E” suffix we’ve occasionally seen on other parts (the FX-8370E being the most prominent example). The A12-9800E, A10-9700E, and A6-9500E all slip into a 35W thermal envelope, at the expense of a couple hundred megahertz of clock speed for both their CPU cores and graphics processors.
AMD’s internal benchmarks suggest that Bristol Ridge desktop parts are nipping at the heels of Intel’s Skylake processors for regular desktop tasks, although the usual truckload of salt should probably apply to all of these claims. For example, the company says that in PCMark 8 Home Accelerated, an A12-9800 APU delivers performance equivalent to a Core i5-6500. It’s worth noting that the Accelerated version of PCMark 8 uses OpenCL for some of its tasks, however, a configuration which might favor the AMD chip’s IGP.
That powerful Radeon IGP does seem to give the A12-9800 a leg up in the 3DMark 11 Performance test. That benchmark runs at an undemanding 1280×720 resolution, and it’s been superseded by the 3DMark Fire Strike and 3DMark Sky Diver benchmarks. Still, AMD says the A12-9800 doubles the performance of the Intel HD Graphics 530 IGP in the Core i5-6500 at 65W. The company also claims the 35W A12-9800E can deliver 88% better results in 3DMark 11 Performance versus the 35W Core i5-6500T.
Those results might make that top-end Bristol Ridge APU well-suited for basic gaming, but we’d be interested to see more user-experience-centric numbers like frame times (or even just average FPS) for these IGPs. 3DMark’s index scores might be handy for broad comparisons, but they don’t tell us anything about the actual gaming experience one might have with an AMD IGP.
For example, a $130-ish Radeon RX 460 4GB card like the one we recently reviewed turns in a 3DMark 11 Performance result of 9133 on one of our X99 testbeds, while the A12-9800’s index score is actually just 3581 on its AM4 platform, according to AMD’s materials. The RX 460 is what we would call a “solid” basic gaming experience, so we wouldn’t expect to be blown back by the performance of the IGP on even this highest-end Bristol Ridge APU.
AMD also goes out of its way to highlight the performance-per-watt of these chips relative to the Intel competition, and it’s here we need to raise a red flag. The company performed its efficiency calculations by subbing in a 91W Core i5-6600K for the 65W i5-6500 in comparison to the A12-9800, and that same Core i5-6500 for the 35W Core i5-6500T in comparison to its 35W A12-9800E. We won’t lend these results any credibility except to say that when the goalposts are this mobile, you can make any claims you want. We have no idea why AMD made this switcheroo—it’s about as subtle as dropping a hot coal in someone’s pocket.
Like Intel’s recently-released Kaby Lake CPUs, Bristol Ridge offers hardware acceleration for the HEVC and VP9 video codecs. It’s worth noting that these APUs can only perform hardware encoding and decoding of 4K content for HEVC, however—VP9 support is limited to 1080p content. Kaby Lake, on the other hand, can decode 4K VP9 content in hardware. Given that the next-generation codec wars still appear to be in full swing, Bristol’s limited VP9 support may not be that important in the grand scheme of things.
Chipsets fill another hole in the AM4 platform puzzle
Along with its full lineup of Bristol Ridge desktop APUs, AMD is also giving us a first glance at the chipsets that will power those systems. The company isn’t introducing its enthusiast chipsets now—those will presumably be held back until the Zen launch—but it is filling out the rest of the range for us.
The highest-end chipset AMD will be introducing in Bristol Ridge OEM systems is B350, which will take the place of the 970 chipset for AM3+ systems and the A78 chipset for FM2+ systems in the platform lineup. In turn, the A320 platform will supersede the 760G and A68H chipsets that supported low-end AM3+ and Socket FM2 systems. Straightforward enough.
One potentially interesting thing about the AM4 platform is that AMD will also be introducing small-form-factor versions of its chipsets for (we assume) equally small-form-factor PCs. The X300, B300, and A300 chipsets are all small-footprint versions of the platform for these mini-PCs. Though AMD didn’t say as much, we’re guessing that “X” chipsets will be its highest-end platform for both Bristol Ridge and Zen CPUs alike.
AMD says it pulled most of the northbridge and southbridge features on its motherboards onto the CPU with the move to AM4, a move that might explain the rather barren-looking PCBs on the prototype motherboards we’ve seen running Zen CPUs thus far. Bristol Ridge APUs will offer eight lanes of PCIe Gen3 from the CPU for graphics cards, two channels of DDR4 memory, four USB 3.0 ports, two SATA ports, and two general-purpose PCIe Gen3 lanes from the SoC that can be used for connecting peripheral devices from the motherboard or to power an NVMe M.2 slot. It seems likely that Zen CPUs will have much more to offer on these points.
In turn, the chipsets (or platform controller hubs, as Intel calls them) don’t have a lot left to do. The B350 chipset provides two USB 3.1 Gen2 ports, two USB 3.0 ports, and six USB 3.0 ports. It also offers two SATA ports, one SATA Express connector, and six lanes of general-purpose PCIe Gen2 connectivity. The B350 controller can also perform RAID 0, 1, or 10 on connected storage devices.
The lower-end A320 chipset drops one of the USB 3.1 Gen2 ports, two lanes of PCIe Gen2—and that’s about it. AMD didn’t reveal what its 300-series small-form-factor chipsets will look like yet, but the controller does drop RAID 10 support.
As we noted at the beginning of this piece, AMD is exclusively offering seventh-gen APUs and motherboards to its OEM partners right now. HP and Lenovo are just two of those partners that have designs lined up with these new desktop APUs inside, and more are apparently in the works. AMD says “we’ll announce channel parts later,” so we’d expect retail boxed processors and motherboards from the usual suspects to be announced separately later this year.
What’s perhaps most exciting about today’s announcement is that it gives us a good picture of what the ecosystem around Zen CPUs might look like. Builders who choose Zen CPUs and Bristol Ridge APUs will be able to avoid the labyrinthe range of coexisting-yet-incompatible motherboard and chipset offerings available for today’s Socket AM3+ CPUs and Socket FM2+ APUs. Instead, they can just purchase the motherboard with the feature set and price tag that fits best with their needs, much as Intel builders already can with the 100-series chipset lineup and Socket 1151 CPUs. That’s a major step forward in builder-friendliness. Now, AMD just needs to deliver on Zen’s performance claims, and life may be rosier for the red team. No pressure, folks.