Discrete HTPC GPU Shootoutby Ganesh T S on June 12, 2011 10:30 PM EST
HTPC enthusiasts are often concerned about the quality of pictures output by the system. While this is a very subjective metric, we have decided to take as much of an objective approach as possible. Starting with our HTPC reviews, we have been using the HQV 2.0 benchmark for this purpose. The HQV benchmarking procedure has been heavily promoted by AMD, but it is something NVIDIA says it doesn't optimize for. Considering the fact that there aren't any other standardized options available to evaluate the video post processing capabilities of the GPUs, we feel that HQV benchmarking should be an integral part of the reviews.
However, HQV scores need to be taken with a grain of salt. In particular, one must check the tests where the GPU lost out points. In case those tests don't reflect the reader's usage scenario, the handicap can probably be ignored. An example is cadence detection. Only interlaced streams with non-native frame rates (i.e, 24p content at 60i, 25p content at 50i etc.) need this post processing. Even within this, it is streams requiring 3:2 cadence detection that are most common. Streams with 2:3:3:2 and other fancy patterns are almost non-existent in most usage scenarios. So, it is essential that the scores for each test be compared, rather than just the total value.
The HQV 2.0 test suite consists of 39 different streams divided into 4 different classes. In our HTPC(s), we use Cyberlink PowerDVD 11 with TrueTheater disabled and hardware acceleration enabled for playing back the HQV streams. The playback device is assigned scores for each, depending on how well it plays the stream. Each test was repeated multiple times to ensure that the correct score was assigned. The scoring details are available in the testing guide from HQV.
In the table below, we indicate the maximum score possible for each test, and how much each GPU was able to get. The NVIDIA GPUs were tested with driver version 270.61 and the AMD GPUs were tested with Catalyst 11.5.
|HQV 2.0 Benchmark Shootout|
|Test Class||Chapter||Tests||Max. Score||NVIDIA GT 430||MSI GT 520||AMD 6450||Sapphire 6570||MSI 6450|
|Video Conversion||Video Resolution||Dial||5||5||4||5||5||4|
|Dial with Static Pattern||5||5||5||5||5||5|
|Film Resolution||Stadium 2:2||5||5||0||5||5||5|
|Overlay On Film||Horizontal Text Scroll||5||5||5||5||5||5|
|Vertical Text Scroll||5||5||5||5||5||5|
|Cadence Response Time||Transition to 3:2 Lock||5||5||5||5||5||5|
|Transition to 2:2 Lock||5||5||0||5||5||5|
|Multi-Cadence||2:2:2:4 24 FPS DVCam Video||5||5||0||5||5||5|
|2:3:3:2 24 FPS DVCam Video||5||5||0||5||5||5|
|3:2:3:2:2 24 FPS Vari-Speed||5||5||0||5||5||5|
|5:5 12 FPS Animation||5||5||0||5||5||5|
|6:4 12 FPS Animation||5||5||0||5||5||5|
|8:7 8 FPS Animation||5||5||0||5||5||5|
|Color Upsampling Errors||Interlace Chroma Problem (ICP)||5||5||5||5||5||5|
|Chroma Upsampling Error (CUE)||5||5||5||5||5||5|
|Noise and Artifact Reduction||Random Noise||SailBoat||5||5||5||5||5||0|
|Compression Artifacts||Scrolling Text||5||5||3||3||5||0|
|Upscaled Compression Artifacts||Text Pattern||5||3||3||3||3||0|
|Image Scaling and Enhancements||Scaling and Filtering||Luminance Frequency Bands||5||5||5||5||5||5|
|Chrominance Frequency Bands||5||5||5||5||5||5|
|Resolution Enhancement||Brook, Mountain, Flower, Hair, Wood||15||15||15||15||15||15|
|Video Conversion||Contrast Enhancement||Theme Park||5||5||5||5||5||5|
|Beach at Dusk||5||5||5||5||5||5|
|White and Black Cats||5||5||5||5||5||5|
|Skin Tone Correction||Skin Tones||10||7||7||7||7||7|
A look at the above table reveals that there is not much to differentiate between the AMD 6450, GT 430 and 6570. The GT 430 scores in between the 6450 and 6570. However, the GT 520 and the DDR3 based MSI 6450 stand out because of their low scores.
In our GT 430 review last October, we were willing to give it some leeway because it lost out in the bulk of the cadence detection tests. The GT 520 is in a similar situation here. The all-important 3:2 pulldown is performed correctly. However, none of the other cadence detection tests passed. GT 520 also has other issues in general which cause it to get a lower score than what the GT 430 obtained in its initial review. We will take a look at how the GT 520 fares in the other tests before delivering the final verdict.
The DDR3 based 6450 misses out on the bulk of the scores because it is unable to perform denoising in a proper manner. When AMD was contacted about this, they admitted the issue and indicated that they were working on a fix. However, they pointed out that the problem was only for standalone files and not Blu-ray discs. To our surprise, we found that denoising worked properly in PowerDVD irrespective of ESVP when the HQV Benchmark Blu-ray was used! We decided not to let that alter the scores above. Blu-rays are already mastered carefully, and don't need as much post processing as local files from recorded TV shows or camcorder files. The low score of the DDR3 based 6450 will probably improve a great deal after driver updates, but we will consider only playback of files on the hard drive in the rest of this review.