The New AMD “Kaveri” Range of APUs

In the CES 2014, AMD spent a better part talking about a new interesting, Steamroller-based x86 processor architecture. Christened as “Kaveri”, AMD has done a overwhelming lot of work on its new processor. With Heterogeneous System Architecture features and a new 28 nm manufacturing process from GlobalFoundaries, this CPU aims for better interplay between the system and software developers.kaveri

The Architecture

In order to better utilize available die space AMD had to renew its lithography from a CPU optimized 32 nm SOI, that allowed for clock rates as high as 4.4 GHz, to a 28 nm bulk silicon process, called as APU optimized process by AMD. By opting for slower, higher-resistance transistors, it manages to fit more dies per cm3. The fundamental graphics unit a.k.a the Compute Unit, is replicated over and over and AMD calls it the Compute Core, a HSA-enabled, programmable, capable of running at least one process parallel and independently of others in its own context and virtual memory space. This enables amalgamating CPU and GPU resources, yielding APUs equipped with 8 and 12 compute cores, all accessing to the same unified coherent memory space. AMD claims that the APU is able to handle 12 threads running parallel, and thus technically, a 12-core device. A compelling nomenclature when the mainstream market buzzes around dual and quad-cores.

Similarly the transition to Steamroller aims to get single-threaded performance to higher levels. The instruction caches have also been augmented, The L1 cache previously, 64 KB is now a 96 KB three-way set associative, and the L2 branch target buffer has also been increased from 5000 to 10,000 entries. The integer clusters can access the microcode ROM simultaneously now and also allows for two simultaneous STOREs.

Real-world usage Implications

Comparing with Intel’s “Haswell”, Kaveri is undoubtedly slower but still improved that previous generation “Piledriver” based “Richland”. However, thanks to the embedded Radeon R9 dies on board, it simply blows off the Intel’s integrated HD graphics. For games such as Skyrim and BioShock infinity, Kaveri easily pumps out playable frame rates. It also can handle most games at FullHD at decent detail and FPS. Kaveri also includes TrueAudio support and thus is able to offload sound processing, akin to its Radeon R9 series.

Although Kaveri lacks fixed-function support for accelerated H.265 decoding, support for accelerating playback of H.264, VC-1, MPEG-2, MVC, and MPEG-4 is available. With HSA and OpenCL applications such as multimedia editors are likely to get performance gains.

The flagship of this series shall be the top-end 95 W A10-7850K, however, the real emphasis of Kaveri is the niche lower-power segments. According to AMD reps, Kaveri is designed optimally for the mid 35 to 45 W range while scaling as much as 95 and as low as 15 W. AMD envisages for APUs to sport not only in gaming oriented desktops but also in notebooks, embedded environments, and servers. And for this it had to compromise on manufacturing side. By balancing transistor density, the new Kaveri flaunts a 512-shader Radeon graphics core, albeit sacrificing CPU speed.

Gone are the days of old mammoth desktops. With the world moving to embedded era, there has been an increased demand for low-power high-performance. Intel has been dancing to this mantra for quite a while, with the notable exception being the graphics sector. Intel’s Iris Pro is just too much expensive. With low power and more-than-average performance and an excellent graphics, the AMD “Kaveri” series, might just turn the tables. Stay tuned to TechGipsy for more updates on latest technology.

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