ADFS 2011 Wrapup & AMD Lynx Platform Tests



Company: AMD
Author: James Prior
Editor: Charles Oliver
Date: July 18th, 2011

Brilliant HD In Action

Right now then, consumers will be able the leverage the APU power through media consumption. We saw with the AMD Brazos platform that basic mainstream home theater tasks can be handled with ease by a low clocked dual core with single SIMD - the E-350 APU. However, some HTPC builders and owners require a little more from their boxen, and that's where the A-series can fill in the gaps.

Like the E-series APUs, the A-series APUs also feature AMD's UVD 3 hardware, which accelerates many video decode operations, including Blu-ray3D and DiVX, as well as MPEG-2 and H.264. The output of the UVD block can be processed by the Radeon cores in the Vision Engine. With the extra SIMD horsepower, more post processing effects can be added, realtime, to the video playback, for extra fidelity. Upscaling and lighting/contrast adjustments can be added to video, which aren't available on other integrated graphics solutions. AMD provide a demo mode that allows split screen to see the effects in real time as contrasted with the original unprocessed video.

AVC video enhanced by Picture Perfect HD

The default options for AMD video enhancements known as Picture Perfect HD are a good starting point for HTPC enthusiasts to fine-tune their viewing experience. Depending on the content, they may want to override the defaults and adjust de-interlacing method, tweak color vibrancy and flesh tone correction settings or even disable them in preference to using software adjustments. Tweaking the output to the display is easily done using the Vision Engine Center display tasks, to adjust over/underscan and color properties. Not all HDTV's support per-input display calibrations, instead applying color, saturation etc. controls to all inputs. In those cases you can tweak the display output using the Display Color controls for color correction, brightness and contrast, as well as using EDID data. Below you can see the results of testing interlaced video playback, with AMD vector adaptive deinterlacing enabled and enforce smooth playback disabled, with Picture Perfect HD enabled including full range contrast, in split-screen demo mode (click pic for full-size image).

APU Video Deinterlacing Test

Applications like Cyberlink MediaEspresso can leverage the hardware decode and encode abilities of the AMD A-series APU to reduce transcode and processing time for converting video. Here we compare the stock performance with 1333MHz memory of the CPU vs. the APU by enabling hardware accelerate encode and decoding within the application.

Turning on AMD APP and using the Radeon Cores decreased processing time by 165 seconds, a performance increase of approximately 33.5%.

For gaming, it's obvious that being a mainstream desktop part, high resolution (1080p) and high quality settings are going to be out of the question. Dropping to more mainstream resolutions, like 720p (1280x720 or 1368x768) and mid-HD resolutions (1600x900 or 1680x1050), things get more fun. All but the most punishing titles will be playable at medium settings with 2-4xAA and 8xAF. The first generation of DirectX11 games used Dx11 functionality for ultra-quality effects, like HDAO/SSAO and advanced shadows. On mainstream graphics these are the first settings to get turned off, as there isn't enough GPU power for them.

We used 3DMark 11 performance test to show the difference in capabilities of various configurations:

Here the O/C configuration is the bClk increased to 150MHz with CPU multi x23.5 for 3.5GHz CPU, and GPU overclocked to 775MHz. The non-O/C results are at 2.9GHz/600MHz.

Overclocking the APU and memory increases 3DMark11 P-mark result by 45%.

Next we tried various GPU configurations. First with APU and HD 6670 dual graphics, and then overclocked APU with 6670. Next we overclocked the APU x86 cores but underclocked the GPU cores to 300MHz. Finally we added different discrete GPUs as the primary adapter, results were run at APU stock clocks with 1333MHz RAM, APU GPU unused.

If you pair the A8-3850 CPU cores with a discrete HD 5550 GDDR5 you get about the same performance as our overclocked APU results. If you took that ~$70USD and bought an ~$85 HD 6670 instead, enabling Dual Graphics CrossfireX increases performance by 73.5% over the 5550 results, and . Interestingly, overclocking the APU decreases performance, indicating the power containment is reducing CPU performance for gaming. Running the APU overclocked on the CPU cores but the GPU underclocked, with the HD 6670 as primary and only GPU increases performance by 68% against the stock APU by itself, and 21.2% over running the APU with a HD 5550. Engaging dual graphics with the HD 6670 increases performance by 43% over using the 6670 alone, and 141% over using a stock A8-3850 APU. If that sounds high, recall that the 6670 is equipped with an extra SIMD, higher core clocks, four more texture units, and has much faster memory (128-bit GDDR5 with 4 RBEs, vs. 64-bit DDR3 and 2RBEs.).

Increasing your spend from $85 to ~$110 HD 6770 gives you a 2% increase for 30% more money. Bumping up to a total of ~$150USD, and a Radeon HD 6850, you get a 225% increase in performance over a stock APU, and ~35% increase in performance over APU dual graphics with HD 6670 or single 6770. Double the money, get a third more performance - an elegant demonstration of the law of diminishing returns.

Image Quality

To examine gaming image quality we tested Anisotropic Filtering (AF) quality by looking at angle dependence and mipmap kernel transitions. The Radeon Cores in the A8-3850 are designated as the Radeon HD 6550D, but are based on the Evergreen Redwood (HD 5500, 5600) configuration. The newer Radeon HD 6500, 6600 discrete cards use the Turks design, which is an updated Redwood with improved (amongst other things) render-back end (RBE) hardware. The improved hardware results in better AF performance in these tests.

Sumo Anistropic Filtering Angle Dependency
Sumo Anisotropic Filtering Kernel Transitions

The Radeon 6550D in the A8-3850 doesn't have the improved RBEs of Turks, and so is more susceptible to shimmer in isolated cases. You can read more about that issue in our IQ investigation here. Even with this outlier issue that most people won't ever notice, the image quality and features of the APU graphics are far better than anything else you'll find in an integrated solution, chipset or on-CPU.

Vision Engine Center Options

In single graphics mode, the standard ATI Radeon HD 5000 series options are available; Anti-Aliasing methods of MSAA (standard, upto 8x), Narrow Tent (up to 12x), Wide Tent (up to 12x) and Edge Detect (up to 24x), plus Adaptive Anti-Aliasing (Dx9) and SuperSampled AA (Dx9). A-series APUs also support AMD's Morphological Anti-Aliasing, a post processing effect you can read more about here.

Anti-Aliasing Modes

Adding a second GPU unlocks higher levels of AA available, 16xMSAA, 24xEDAA and 32xWTAA, all of which can be combined with AAA or SSAA. These driver overrides are great options for older legacy games which don't have any in-game IQ enhancments or titles that run exceptionally well and the extra GPU performance can be put to good use.

More Anti-Aliasing Modes