Via intros QuadCore processor with guess how many cores

Because 'Nano X4' would be too obvious
— 11:01 PM on May 11, 2011

Early this year, Via introduced its Nano X2 processor, a dual-core implementation of its Isaiah architecture built on TSMC's 40-nm chip fabrication process. Today, Via is announcing a new product, the QuadCore processor, that combines a pair of Nano X2 chips on a single package to deliver a low-cost, low-power CPU whose position in the market is fairly distinctive.

We visited Via-Centaur's Austin, Texas offices yesterday, where we chatted with Centaur President and Founder Glenn Henry and Via VP of Marketing Richard Brown. We came away with some fresh details on the QuadCore processor and a better sense of Via's future plans as an intriguing third-place supplier of x86-compatible PC processors.

Initially, Via is introducing a single model of the QuadCore, the L4700, rated for 1.2GHz operation and a maximum thermal and power envelope (TDP) of 27.5W. This CPU has a front-side bus speed of 1333MHz and a total of 4MB of L2 cache. However, as with other recent PC processors, those specifications only tell a part of the story.

New on the QuadCore's feature list is something called Adaptive Overclocking, which isn't really overclocking in the void-your-warranty sense we've come to know and love. Instead, Adaptive Overclocking enables the CPU to range dynamically up to frequencies as high as 1.46GHz, provided there's sufficient thermal and power headroom available, much like Intel's Turbo Boost. Via indicates this possibility by listing the QuadCore's clock speed as "1.2+ GHz," just to keep folks guessing. Much like Intel's most recent incarnation of Turbo Boost in its Sandy Bridge chips, Adaptive Overclocking will allow the QuadCore push beyond the chip's specified TDP peak for short periods, provided system temperatures will allow it.

The QuadCore ranges up to 1.46GHz under load

The QuadCore's dynamic frequency scheme is complicated by the fact that it involves two separate chips, each with dual cores. Dynamic power and frequency management happens on the chips themselves, using power consumption estimates provided by the VRMs, in concert with the operating system's P-state requests. The chips then coordinate, Henry told us, by talking over a "side channel" of wiring between them, built into the CPU's package. Each chip can range up in frequency independently of the other, provided there's headroom available between the two.

When the cores are idle—the vast majority of the time, in most systems—they will drop to lower frequencies and voltages, of course, and clock gating will kick in to save power. Via doesn't yet have power gating and separate voltage islands like we've seen in some Intel and AMD processors, however. Henry hinted those are likely to come in Via's next chip.

The rest of the inter-chip communication in a QuadCore processor happens via the front-side bus, just as it did in Intel's quad-core, Penryn-based Yorkfield CPUs, for instance. Because the QuadCore uses Via's "V4" front-side bus technology—which is very similar to Intel's FSB—and the same pinouts as prior Via CPUs, this new processor is instantly compatible with Via's existing chipset and motherboard infrastructure. Still, there's work yet to be done. Although today is the CPU's official unveiling and the building-block Nano X2 parts are already shipping, Via doesn't expect the QuadCore to enter production until the third quarter of this year, because the quad-core part requires additional qualification.

The Nano X2 (left) and QuadCore (middle)

Once it arrives, Via expects the QuadCore to find its way into a range of products, from netbooks to low-cost desktops, small-form-factor PCs, and mini servers. However, we here in North America can probably expect to see the QuadCore arrive first in motherboards, probably of the Mini-ITX variety, aimed primarily at embedded systems and such. Outside of a few notable exceptions like the Samsung NC20, Via has had precious little success getting the Nano and its derivatives into consumer products here. The Nano has gained more traction in emerging markets like China and India—markets that are more price-sensitive and less brand-sensitive than ours. That may be where the QuadCore finds its footing, as well. Brown couldn't yet point to any upcoming notebooks or low-cost desktops destined for these shores with a QuadCore CPU inside.

If the QuadCore can't crack the consumer market here, that may be a shame, because it stands to occupy a spot in the x86 firmament not really served by any other CPU. The "Isaiah" core, you may recall, has a true out-of-order execution engine tuned to deliver decent per-clock performance at relatively low-power operation. In many ways, it may be most similar to the Bobcat core in AMD's "Brazos" APU, though with somewhat higher per-clock performance. The major difference, of course, is that the QuadCore has four cores, while Brazos and Intel's Atom platforms top out at two. With no higher-end CPU business to threaten, Via can offer a low-cost quad-core option with a promising performance story for a range of needs, from light-duty computing to multimedia playback and even some gaming.

The firm showed us selective results from its own internal benchmark bake-offs versus an AMD E-350 APU, and the QuadCore won by margins ranging from 5% in SysMark 2007 to 28% in CPUMark 99 and 100% in Cinebench R10. (The margin in Everest's AES encryption bench was 1871% in favor of the QuadCore, thanks to Isaiah's built-in encryption engine.) When paired up with a discrete GeForce graphics card, the QuadCore even took on one of the Internet's most enduring memes by churning out acceptable frame rates in a live demo of Crysis 2.

With a TDP of 27.5W, the first QuadCore isn't positioned exactly opposite Brazos (9-18W TDPs) or the netbook and desktop Atom variants (~13W) in terms of power consumption, but its power draw is still sufficiently low to fit into small notebooks (say, in the 12-13" range), all-in-one PCs, and other small form factors. Brazos' mark of 18W is really a more comfortable fit for netbooks and such, and Via plans to reach that TDP level with another, not-yet-announced variant of the QuadCore, likely running at 1GHz. That version will, obviously, be a more direct threat to AMD's baby Fusion APU.

Total platform power consumption is really a more important issue than CPU TDP alone, and the QuadCore doesn't have as many traditional chipset functions integrated into it—not a memory controller, graphics engine, or PCI Express—as the latest Atom or AMD's APUs. However, Henry was quick to point out that all of that functionality is there in a Via-based system, potentially in just two chips like the competition—or, in the case of the QuadCore, one chip and one dual-chip package—thanks to Via's single-chip core logic solution. That I/O chip's contribution to total power draw is relatively small, at around 4W. Also, crucially, chipset silicon typically is built on older process nodes, said Henry, so it's cheaper to manufacture. Locating graphics and the rest there keeps costs down, which is clearly a key to Via's strategy.

Glenn Henry explains what's where in an expanded version of the Nano die

Chipset support may be something of an issue for the QuadCore. Via has two basic options right now, as Brown explained. There's a single-chip core logic offering, the VX900, with DirectX 9-class graphics and robust acceleration for H.264 video decoding, and there's the VN1000 dual-chip set with DX10.1 graphics and only partial H.264 decode acceleration. Neither is an ideal choice, obviously. A better answer is in the works in the form of new chipset with DX11-class graphics, but it's not ready yet. Furthermore, Adobe doesn't take advantage of Via's H.264 decode acceleration in its Flash video software, and that isn't likely to change any time soon.

On the plus side, H.264 playback is something of a binary it-will-or-it-won't type of performance question, and the QuadCore should have enough muscle to decode and play H.264 video streams without additional assistance, albeit at the likely expense of battery life versus dedicated hardware. Henry expressed confidence the Nano X2 would do fine, as well.

Our next steps, obviously, will have to include getting our hands on a QuadCore-equipped laptop or motherboard for some testing. We're intrigued to see how it stacks up against Atom and Brazos, and how well it handles a range of common computing tasks.

Via's next steps seem to be fairly evident, as well. Henry told us they're working on their next chip now, which will involve a true refresh of the Isaiah architecture, with improvements for efficiency and performance. He let slip that this next chip will be manufactured on a newer process node, 28 nanometers, with "more than two cores on a single die," but beyond that, he wasn't ready to divulge details just yet. The logical thing would be to put four cores on a chip, perhaps with an integrated memory controller and maybe even graphics, but we'll have to wait for official confirmation of those plans down the road.TR

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