A Reference Platform – But not a great one

We test the reference design for the A4-5000 Kabini notebook provided by AMD.

Believe it or not, AMD claims that the Brazos platform, along with the "Brazos 2.0" update the following year, were the company's most successful mobile platforms in terms of sales and design wins.  When it first took the scene in late 2010, it was going head to head against the likes of Intel's Atom processor and the combination of Atom + NVIDIA ION and winning.  It was sold in mini-ITX motherboard form factors as well as small clamshell notebooks (gasp, dare we say…NETBOOKS?) and though it might not have gotten the universal attention it deserved, it was a great part.

With Kabini (and Temash as well), AMD is making another attempt to pull in some marketshare in the low power, low cost mobile markets.  I have already gone over the details of the mobile platforms that AMD is calling Elite Mobility (Temash) and Mainstream (Kabini) in a previous article that launched today.

This article will quickly focus on the real-world performance of the Kabini platform as demonstrated by a reference laptop I received while visiting AMD in Toronto a few weeks ago.  While this design isn't going to be available in retail (and I am somewhat thankful based on the build quality) the key is to look at the performance and power efficiency of the platform itself, not the specific implementation. 

Kabini Architecture Overview

The building blocks of Kabini are four Jaguar x86 cores and 128 Radeon cores colleted in a pair of Compute Units – similar in many ways to the CUs found in the Radeon HD 7000 series discrete GPUs.  Josh has written a very good article that focuses on the completely new architecture that is Jaguar and compared it to other processors including AMD's previous core used in Brazos, the Bobcat core. 

While I would definitely ask you all to read the full article, here is a summary of Josh's thoughts on the new Jaguar cores coupled with GCN:

Jaguar is a massive redesign of the Bobcat architecture that improves IPC in single threaded applications by up to 20%, and also increases the top clockspeed while still retaining the same thermal characteristics of the earlier part.  It also goes from a dual core part to a true quad core product.  Graphics performance has increased dramatically as well with the GCN architecture in place as well as further power and thermal optimizations which allow the product to run at faster speeds as well.

This product is intended for the sub-5 watt market all the way to 15 watts.  It is arguably the most feature packed product in this category, and the performance is class leading as well.  The core size is around the same as the latest ARM Cortex A15, but it should perform better per clock than that particular product.  Not to get overly excited though, the Cortex A15 is still more energy efficient due to the low power oriented ARM ISA.  Having said that, Temash at 3.9 to 5 watts should give a better user experience in a tablet than a comparable A15 based SOC.  We personally played DiRT Showdown on a Temash tablet and the experience was impressive.  Intel has not released their 22 nm based Silvermont products, so AMD has a nice window of opportunity to ship these advanced, low power units with next generation graphics performance and technology.

The original Bobcat architecture was very forward looking at the time, and Jaguar has added to that without sacrificing power consumption for improved performance.  The addition of GCN based graphics also opens the door to greater performance in workloads that can actually utilize hUMA based architectures and graphics based parallel computing.  Jaguar looks to be an impressive update and should allow AMD to move aggressively into the tablet market, not to mention maintain their presence in the ultra thin-and-lights and the budget notebooks.

The A4-5000 Kabini Reference System

The Kabini, A4-5000 reference notebook is a 14-in thin and light design that, while not quite hitting the Intel Ultrabook level of thinness, is just about 0.75-in thick.  It has a brushed metal back cover but the rest is made of plastic.  Here are the specifications:

Test System Setup
CPU AMD A4-5000 APU (Kabini)
Display 14-in 1920×1080
Memory 4GB DDR3-1600 (single DIMM)
Hard Drive Toshiba 1TB 5400 RPM 2.5-in
Sound Card On-board
Graphics Card AMD Radeon HD 8330 (Kabini)
Graphics Drivers Beta for Kabini
Power Supply None
Operating System Windows 8 Pro x64

I know that some of the samples shipped with hybrid hard drives; our did not.  That really put a damper on the testing process as solid state storage, whether a full SSD for a hybrid like the Seagate 500GB SSHD can change the usability perception of a system dramatically.

At a first glance the hardware seems pretty decent for a target price range of $400-500 but there are some issues I had with this implementation we'll get into later.  The 1080p display was pretty nice and had solid viewing angles and high maximum brightness levels for a low cost reference system. 

The keyboard and touchpad left a lot to be desired though and I found typing on it difficult with a lot of flex and uneven keys.

Our Kabini reference machine sports headphone and mic jacks, two USB 2.0 ports and an optical drive on the right hand side. 

On the left we find a USB 3.0 port, HDMI out (in a Mini DisplayPort connector), VGA output, a hinged Ethernet port, the power connection and the ventilation for the system cooling.  During use this area did not get overly warm thanks to the lower levels of the A4-5000 APU. 

As I said above, the reference machine didn't quite hit at the thinness of some of the Ultrabooks we have around the office but for a quickly constructed device it is very portable.  The battery life we measured helps that out a LOT as well!

The A4-5000 reference machine only shipped with a 45 WHr battery – fairly small in the world of notebooks.  For reference, our Ivy Bridge reference machine had a 67 WHr battery and a typical 9-cell battery from Lenovo is in the 84 WHr range. 

Opening up the bottom of the device reveals of a fairly empty chassis thanks to the small and low power components of Kabini.  The optical bay takes up quite a bit space (top left).

AMD filled only a single SODIMM slot with a 4GB module – because Kabini only has a single channel memory controller this does not adversely affect performance.  The SODIMM runs at 1600 MHz, the maximum out of box speeds supported by the Kabini APU. 

The Toshiba hard drive might have been the most disappointing product in the system build, but likely does represent the type of storage you get in a $500 laptop in today's market.  Replacing this with an SSD or even a hybrid solution will make a large difference for usability and responsiveness.

Removing the small heatsink and fan combination reveals the A4-5000 APU – a tiny little thing that is built on the 28nm process technology at TSMC. 


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