by Anton Shilov , Alexey Stepin
09/14/2007 | 12:52 PM
UPDATE: Adding HQV HD tests results obtained on the GeForce 8600 GTS ForceWare 163.69 drivers.
Today, a PC cannot be imagined without capabilities for playing multimedia content. Even cheapest entry-level PCs are equipped with an audio adapter, let alone a graphics core. The leading developers of computer chips are trying to endow the modern PC with a still broader range of multimedia capabilities to entice users into upgrading their hardware.
Products with rich multimedia functionality are not necessarily, by the way. For example, a few years ago Intel introduced its integrated 7.1 audio controller called Azalia that could output audio to progressive speaker systems and supported a number of innovative technologies. ATI, the graphics division of Advanced Micro Devices, has introduced an ATI Radeon X1250 graphics core integrated into AMD 690 chipsets which allows to connect modern TV-sets to the PC via the new HDMI interface.
Having a lot of multimedia features is good, but the quality of implementation is no less important. The sheer support for 7.1 audio doesn’t guarantee that modern games and movies will have a high-quality sound – you need an expensive sound card for that. As for HDMI support, you shouldn’t expect a PC with an entry-level CPU and an integrated graphics core to transform into a home theater after you add a HDMI connector to it. More likely, you’ll have to buy a standalone graphics card and a more advanced CPU.
It is about the quality of implementation that we are going to talk in this review.
Sony and Toshiba found themselves unable to reach an agreement on the topic of standardization of new-generation laser discs. As a consequence, the industry has two competing standards today: Blu-ray Disc (BD) from Sony and HD DVD from Toshiba.
Some reviewers consider Blu-ray as winning the battle of formats due to the integration of an appropriate optical drive into the PlayStation 3 console. On the other hand, only 3% of Xbox 360 users have bought an external HD DVD drive, which is indicative of low popularity of high-definition content among owners of Microsoft game consoles. This may also mean that users are not interested in the video capabilities of modern game consoles, be it a Microsoft Xbox 360 or a Sony PlayStation 3.
This supposition agrees with the recent news from the United States that the sales of HD DVD movies grew by 20% in Q2, but the sales of Blu-ray movies declined by 5%. Sales also grew by 37% for HD DVD players and declined by 5% for Blu-ray players. Meanwhile, the simplest HD DVD player from Toshiba costs about $200-300 in the USA, while the most affordable Blu-ray player from Samsung is priced at about $450.
It should be noted that this war of formats is not only about pricing but also about availability, which affects the sales of hardware as well as the sale/lease of intellectual property. Unfortunately, neither Blu-ray nor HD DVD has yet become widespread in Europe, and you still cannot buy BD/HD DVD in some countries.
You can’t buy HD content yet there, but over half of European publishers do not depend on Hollywood finances and choose the more affordable HD DVD format. For example, Luc Besson’s District B13 is already selling at Amazon.com.
One of the formats will eventually come out the winner to replace the DVD, but there is a war of codecs as well: Blu-ray can use H.264, MPEG2 HD or VC-1 whereas HD DVD uses H.264 or VC-1. Notwithstanding the option of choice, virtually all BDs use H.264 while most HD DVDs carry content encoded with VC-1. Different codecs have different hardware requirements, of course.
The newest generations of GPUs – ATI Radeon HD 2400/2600 and Nvidia GeForce 8600/8500 – have got more advanced video-processors than their predecessors, but the developers have taken different approaches here, just as they did in the other areas.
Decoding any video content is a multi-step process, so the resulting success depends on an efficient performance of each step on the hardware. The decoding of H.264 and VC-1 can be divided into four steps:
The most resource-consuming are the first two steps that involve decoding data encoded with entropy algorithms like Context-Adaptive Variable Length Coding and Context-Adaptive Binary Arithmetic Coding, and performing inverse Discrete Cosine Transformation (iDCT). These have not been supported on the GPU until recently, but both GPU developers have introduced appropriate subunits into their new GPUs because these steps are calculated inefficiently on the CPU.
However, VC-1 uses entropy compression algorithms other than those used in H.264 and which are not supported by the current PureVideo HD processor of GeForce 8500/8600. The UVD can perform bitstream processing for both codecs, which is an advantage of Radeon HD 2400/2600 GPUs.
For today’s CPUs, bitstream processing shouldn’t be a big problem even with HD content, yet this technology may come in handy for mobile systems or systems with ultra-low power consumption.
We’ll now check out the CPU load as well as the video playback quality provided by different graphics cards.
To study the CPU utilization as well as video quality in high-definition and typical standard definition we put together a standard testbed with the following configuration:
To estimate the CPU utilization during full-HD/1080p content playback we used the following scenes:
To estimate the CPU utilization during regular DVD playback we used Gladiator movie (PAL, 720x576, 25 fps interlaced, 9 Mbit/s).
To test the CPU utilization during MPEG2 HD (1080i), DivX (640p, 1080p), WMV HD (720p, 1080p), H.264 (720p), VC-1 (720p) playback we used different movies available for download online:
The driver settings remained unchanged. However, according to the HQV HD test suite requirements, we set the Edge Enhancement and Noise Reduction to the maximum on Nvidia GeForce graphics solutions.
The following graphics accelerators participated in our today’s test session:
High-end:
Mainstream:
Entry-Level:
Since we didn’t disable any of Windows processes for the time of this test, the CPU load was fluctuating a little. It means that a difference of 1-2% is insignificant and doesn’t indicate a superiority of one graphics card over another.
The standard Silicon Optix HQV test should be familiar to our readers by our previous report, so we won’t dwell upon the contents of the test here.
Like in our previous review, the difference in DVD playback quality between the different generations and classes of hardware is negligible, although the product from S3 Graphics stands out among the others: it is much better than software MPEG 2 decoding, yet cannot be considered a worthy alternative to the current-generation solutions.
The table shows that each of the Nvidia GeForce processors has a somewhat lower quality of deinterlacing in comparison with the opponent, but the ATI Radeons cannot boast the same level of detail, mostly due to the lack of adjustment of the edge enhancements option in the driver.
Surprisingly enough, the HQV HD test is less detailed than its predecessor, and some places in the documentation are rather vague. Considering that we are unable to re-check the quality on many high-end devices due to their scarcity, the evaluation is often a nontrivial task.
The test itself consists of five steps as follows:
The documentation to the HQV HD test is far from perfect, especially with regards to the film resolution loss test that does not tell explicitly which squares must not produce artifacts for the video-processor to score the maximum amount of points.
If deinterlacing is incorrect, we see a flickering (strobing) of horizontal lines, which means the video processor fails the test. But since we are dealing with movies, not with video as Silicon Optix suggests, motion-adaptive video processing cannot be applied and, theoretically, the highest score cannot be awarded if a flickering of vertical lines is observed. Unfortunately, the latter thing is not explicitly explained in the documentation while Silicon Optix’ representatives couldn’t give us a definite answer, either. That’s why we award 25 points for the film resolution loss test, but do not award 10 points for the film resolution loss test “Stadium” due to the subjectively poor image quality.
However, the problem of a vague description of the test procedure refers not only to the film resolution loss test. Silicon Optix allows manual regulation of noise reduction for the HD noise reduction test. Nvidia caught at the opportunity and implemented very aggressive noise reduction methods into one of its driver versions, declaring a maximum possible amount of points in this test. But these aggressive methods provoke ghosting artifacts in high-contrast dynamic scenes, which makes rather questionable. Being indifferent to such optimizations and to the resulting artifacts, Silicon Optix lowers the value of its test for PC video enthusiasts.
As you see, the graphics cards vary greatly in their results, but considering the vague documentation to the HQV HD test and possible optimizations in the drivers, we can’t claim the numbers will be 100% true to life if AMD and Nvidia program their Avivo HD and PureVideo HD processors more efficiently.
In fact after we tried to use ForceWare 163.69 drivers from Nvidia, we noticed considerable improvements in “HD noised reduction” and “Jaggies” tests on the GeForce 8600 GTS, however, the GeForce 8500 GT demonstrated worse “Jaggies” quality (0 points) compared to results obtained on ForceWare 163.11. As a result, we publish the best possible scores for graphics cards we observed to date.
The GeForce 8600 and Radeon HD 2600 quite naturally boast a higher image quality than the other graphics cards when playing HD DVD, but it is impossible to choose the best out of the two basing on their scores in the HQV HD test.
Modern graphics cards should have no problems playing DVD/MPEG2 streams, but we decided to check out the playback of MPEG2/MPEG2 HD in Microsoft Windows Vista because the new OS had already produced a number of surprises to us.
It seems that all graphics cards, except for the ATI Radeon HD 2900 XT, handle the task well enough, yet it’s not so. As a matter of fact, the GeForce 7950 GX2, and every other graphics card with a 7900 series chip, cannot play a MPEG2 HD stream really well despite the seemingly low CPU load. It is skipping frames and producing a jerky image. Thus, the GeForce 7900 series doesn’t suit for playing MPEG2 HD today.
The CPU load is high for each graphics card in Windows Vista due to imperfect drivers.
The CPU load is high during playback of both a freely distributed 720p clip and a HD DVD movie The Fast and Furious: Tokyo Drift . It is especially high for ATI Radeon HD 2900 XT and GeForce 7950 GX2. There must be some flaw in the drivers for this particular application. Meanwhile, the ATI Radeon X1950 XTX has quite acceptable results.
The CPU load is always low when we’re dealing with 720p format, except for the GeForce 8800 GTS, but when it comes to 1080p we can see that top-performance graphics solutions have in fact no hardware acceleration of video decoding.
There are no problems with playing DivX streams, except that there is no hardware acceleration for DivX 1080p. There are no definite leaders or losers here.
The popularity of WMV HD format is declining, yet we publish the results for the comparison’s sake. You can see that the CPU load level is roughly the same with each graphics card, except for the notorious GeForce 7950 GX2.
DVD format is not anything new, and all modern graphics cards cope with it easily. Unfortunately, it’s not the same for MPEG2 content in 1080i format: the GeForce 7900 series yields a jerky picture, while the new-generation products have a high CPU load.
If the CPU is fast enough, its load is far from critical, but we should note that GeForce 7 series cards have higher CPU requirements than the new-generation solutions while the difference between the Radeon HD 2600 XT and GeForce 8600 GTS is very small. Note that the ATI Radeon X1950 Pro performs well enough, too.
Like with VC-1 codec, the mainstream graphics cards, except for the GeForce 7 series, do not load the CPU much thanks to their rather advanced video processors. However, we can see that decoding of H.264 is currently better implemented in the GeForce 8600 GTS.
The ATI Radeon HD 2600 and X1950 cards easily cope with decoding DivX streams. Nvidia’s GeForce cards are inferior, yet this is not a problem if you’ve got a fast enough CPU.
There’s nothing extraordinary about the results of the test of decoding WMV HD content. The CPU load being low and identical between the different graphics cards, there is no way you can single out a leader or a loser.
Coping with DVD format easily, the ATI Radeon HD 2400 XT acts up with MPEG2 1080i format, having a much higher result in comparison with its opponents.
Interestingly, the Nvidia GeForce 7600 GT, which doesn’t play 1080i MPEG2 in the jerky manner typical of the senior models of the series, has roughly the same results as the GeForce 8500 GT notwithstanding the differences in their video engines.
The diverse video clips do not fit well together into a definite overall picture, yet we can see that entry-level graphics cards, including ATI Radeon HD 2400 XT and Nvidia GeForce 8500 GT, have a high CPU load when playing VC-1 HD clips.
As opposed to VC-1, the graphics cards perform much better when decoding H.264. The CPU load is low here.
The current version of DivX doesn’t suit well for storing full-HD content, which is confirmed by the high CPU load for inexpensive graphics cards. On the other hand, this is largely the drivers’ fault.
The graphics cards have almost the same level of CPU load, which is not very high.
Now it’s time to sum up the results of our tests of video playback under Microsoft Windows Vista. One thing we have seen is that the performance of different graphics solutions depends directly on the support of the hardware capabilities in the driver. Loudly touted video playback features may prove useless while clever optimizations may give a chance to products whose capabilities seem obsolete.
Graphics cards fall into several categories, so let’s discuss each category individually.
The ATI Radeon HD 2900 XT and Nvidia GeForce 8800 GTX/GTS cannot unload the CPU much when playing high-resolution movies, partially due to the lack of advanced video processors and partially due to imperfect drivers. As we’ve had a chance to see, the powerful graphics cards often rely on the CPU when it comes to decoding video streams.
The ATI Radeon HD 2900 XT features an integrated audio controller. Coupled with a DVI → HDMI adapter, this allows enjoying high-quality audio when the publisher prohibits to play 5.1/7.1 audio tracks without HDCP support. The strong point of the Nvidia GeForce 8800 series in comparison with its opponent is low power consumption.
Interestingly, the ATI Radeon X1950 XTX performs well enough against the newer cards, while the dual-chip Nvidia GeForce 7950 GX2 hasn’t been that successful.
Competing to be the best solution for playing Blu-ray and HD DVD content, the GeForce 8600 GTS and Radeon HD 2600 XT generally match each other in the CPU load tests.
The ATI Radeon HD 2600 XT has a lower CPU load when playing VC-1 streams, offers an integrated audio controller and native HDMI support for consumer electronics. The Nvidia GeForce 8600 GTS, on its part, has a very low CPU load when playing H.264 and delivers higher performance in 3D games. Both graphics cards can score equal amount of points in the HQV HD test, but the high-definition post-processing quality heavily depends on drivers.
The bestseller of the previous generation, ATI Radeon X1950 Pro, performs well enough, too. Its opponents from the GeForce 7 series are not so successful.
Entry-level PCs come with inexpensive graphics cards and CPUs, so when the GPU can’t cope with the video load, it is quite possible that the CPU won’t handle a full-HD movie as well.
The new ATI Radeon HD 2400 XT seems preferable to the more expensive Nvidia GeForce 8500 GT due to the lower CPU load as well as such features as an integrated audio-controller and HDMI support. However, you should note the high CPU load when playing VC-1, which may make it impossible to watch a HD DVD movie normally. We can’t say the last-generation products perform well because the peak CPU load is very high.
Thus, ATI Radeon HD 2000 graphics cards can boast somewhat more advanced video playback capabilities than their opponents from Nvidia mostly due to better drivers for Microsoft Windows Vista. Of course, the integrated audio controller and the native HDMI interface are indisputable advantages of AMD’s products as well. However, Nvidia’s GeForce 8 cards are often faster than their direct market rivals in 3D games, so you should weigh all the pros and cons carefully before you choose your own graphics card.