New Samsung Cortex A15-based chip opens door to "Retina" Android tablets

Exynos 5 Dual supports resolutions of up to 2560x1600 as well as SATA, USB 3.0.


The block diagram for Samsung's new Exynos 5 Dual SoC

Samsung has just released details about its new Exynos 5 5250 SoC for mobile devices. This dual-core, 1.7GHz chip is the first one on the market to feature the new Cortex A15 CPU architecture from ARM, which will provide substantially improved performance over the Cortex A9-based chips used in most of today's smartphones and tablets.

The chip also includes ARM's new Mali-T604 GPU designed to power Retina-class displays and support high-performance connectivity options like SATA and USB 3.0. These improvements make it a substantial upgrade over current-generation products like NVIDIA's Tegra 3 or Samsung's own Exynos 4. We'll look at different aspects of the chip to see not just how the Exynos 5 and other Cortex A15 SoCs will benefit current tablets, but also how those improvements could lead to more viable laptop replacements.

The CPU: ARM's Cortex A15

Most ARM processors in today's devices, including the NVIDIA Tegra 3 in the Nexus 7 tablet and all variations of the Apple A5 used in newer iPads and iPhones, use Cortex A9-based designs. The A9 excels in power usage, but is more limited when it comes to performance.

The A15, on the other hand, is designed for devices that need higher performance, and is expected to outperform competing designs like those used in Qualcomm's Krait architecture (which powers, among other things, the US versions of the Samsung Galaxy S III). As we discussed when we first took a look at the A15 architecture, it isn't really intended to replace Cortex A9, which will still have a place in the middle and lower end of the markets where power draw and price are more important than high performance (and in those applications, the A9 will probably be replaced by the Cortex A7 later on). Rather, it's intended to compete with Intel and AMD in performance and features as those companies look to expand into the burgeoning smartphone and tablet markets. We've already seen Intel processors show up in phones like the Xolo X900 and the recently announced Lenovo ThinkPad Tablet 2; Cortex A15 is intended to stem that tide.

A downside to the A15 is that it does increase power usage over the Cortex A9, but Samsung's 32nm process should help to mitigate that issue somewhat. When Apple's A5 processor was moved from 45nm to 32nm using this same "high-dielectric metal gate" (HK+MG) process technology for the $399 iPad 2, it was enough to reduce its power usage and increase its battery life to the tune of 20 to 30 percent.

The GPU: ARM's Mali-T604

The Exynos 5's GPU memory bandwidth relative to its predecessors

While the A15 will increase the Exynos 5's CPU power, its GPU might be more important as Android and Windows tablet manufacturers begin shipping Retina-esque displays to compete with the most recent iPad. The Mali-T604 is purpose-built for such devices: its maximum supported resolution is 2560x1600 (1280x800 doubled), and its 12.8GB/s theoretical memory bandwidth (the same as the A5X in the 2012 iPad) and 800MHz LPDDR3 RAM give it the memory bandwidth it needs to draw an image that large.

In addition to driving high-resolution panels, this graphics power can be used to encode and decode HD video at 60FPS and to push an image to displays wirelessly, though whether this latter feature takes advantage of the Miracast standard (as NVIDIA's Tegra 3 does) remains to be seen. It also supports stereoscopic 3D.

Just as impressive is the Mali-T604's list of supported APIs: DirectX 11, OpenCL 1.1, OpenVG 1.1, and Renderscript are all here, as well as OpenGL ES 1.1, 2.0, and 3.0 support. OpenGL ES 3.0, which brings some features from the standard OpenGL 3.x and 4.x specifications to mobile devices, was just released earlier this week. Full Scene Anti-Aliasing (FSAA, at both 4x and 16x) is also supported.

Aside from the feature list, however, we don't know much GPU's actual performance level beyond its theoretical memory bandwidth. The only clue we have is a promise from Samsung that the Exynos 5 features twice the 3D performance of the old Exynos 4. Using average benchmarks from the GLBenchmark Web site for the Exynos 4 version of the Samsung Galaxy S III and the 2012 iPad, we can try to extrapolate performance from there.


All scores from the GLBenchmark Web site.

So, going from these numbers, a GPU with double the performance of the Exynos 4 would be playing in the same field with the GPU in the A5X, and could possibly outperform it by a decent margin—our theoretical Exynos 5 would win big in the Egypt test, but break just about even in the Pro test. Again, this is all speculation, but this gives us at least a vague idea of how the Mali-T604 is going to perform.

Going beyond tablets

In addition to impressive-looking performance, the Exynos 5 also supports some interesting connectivity options—SATA, UART, USB 3.0, and eMMC 4.5 are all listed as bootable devices on Samsung's site.


The layout of a system running an Exynos 5 SoC.

This says a lot about the kind of devices we might see the processor crop up in. Tablets like Asus's Transformer Prime and Microsoft's forthcoming Surface RT are two ARM-equipped tablets that attempt to replicate the experience of using a laptop using some sort of keyboard and pointing device (a keyboard dock for the Transformer, and Microsoft's promising but as-yet-untested screen covers for the Surface). The addition of support for high-performance and high-capacity storage devices that use USB 3.0 and SATA could make tablets equipped with the Exynos 5 and chips like it even more plausible replacements for low- or mid-tier laptops.

SATA and USB 3.0 support are also features that would be useful in many low-end servers or network attached storage devices—NASes, in particular, have been accumulating more and more server features as they've evolved over the years, and some (like the Iomega px12-450r we looked at a few months back) even include full-fledged Intel processors to power these different services. The Exynos 5's GPU is certainly overkill for this kind of device (and Samsung's product page definitely focuses on the more lucrative phone and tablet use cases), but both the Cortex A15 and the Mali-T600 series are pretty scalable—both can be scaled up or down from one to four processor cores, so as the Exynos 5 lineup expands, seeing it or a processor like it in some sort of server doesn't seem completely out of the question. The presence of hardware virtualization support in the Cortex A15 architecture also paves the way toward potential server usage.

Conclusions

On paper, the CPU and GPU specifications of the Exynos 5 Dual certainly look to be greater than or equal to Apple's powerful A5X in the most important ways. The chip's A15 architecture and 1.7GHz clock speed (compared to the A5X's 1.0GHz) should definitely give it a CPU advantage, while the Mali-T604 looks more than capable of driving a Retina-class display (and, at least according to our educated guessing, should be a bit faster than the quad-core PowerVR SGX543MP4 found in the A5X). Added support for SATA and USB 3.0, on the other hand, give the chip the kind of connectivity it will need to worm its way into the sort of laptop-replacement tablets ARM and its licensees would love to see storm the market.

All we need now is a device that actually uses it.

Fuente:
http://arstechnica.com/gadgets/2012/...droid-tablets/