Posted:2007-05-14 By Video card review Number of View:38326
RADEON HD 2900 XT REVIEW AND
BENCHMARK
By :Video card review
Posted:2007-05-14
xtreview is your : Video card - cpu - memory - Hard drive - power supply unit source
In last November NVIDIA released the GeForce 8800, this was the first graphics chip DirectX 10 ready ( API 3D new generation : Windows Vista ). We waited for a fast counterpart from AMD but the R600 made a serious delay. And today AMD finally released the R600 which arrives today with practically six months of delay !
The new AMD graphics processor officially received the name Radeon HD 2900 XT. From the start, we notes the removed X prefix which characterized for several years graphics chips Radeon , now as replacement AMD use the prefix HD, supposed to insist on functions high-definition . Today the Radeon HD 2900 XT, is the high end model , AMD plan to release in this summer medium and entry range version with Radeon HD 2400 and 2600.
DirectX 10!
We already talked about DirectX 10 (the new 3D programming library version from Microsoft ) detail in our GeForce 8800 GTX review, Let us again note that DirectX 10 is exclusively available with Windows Vista, the last operating system from Microsoft. Technically, this new API was entirely rewritten in order to get rid from old DirectX versions support , the objectives was to reduce to the maximum the processor consumption by this new API while decreasing latency times. These details can seem unimportant, however they allow to gain many cycles clock which developers will use for other tasks.
DirectX 10 calculation precision remains fixed at format FP32 however with some changes on round-offs calculation level , Microsoft try to bring the GPU closer to the standard IEEE 754. With DirectX 10, Microsoft proposes a programming model completely unified. Concretely, developers can now program pixel and vertex shaders using the same language and instructions. DirectX 10 present also passage to Shader Model 4.0. A synonymous passage, as with each new API the maximum number of instructions, number of authorized constants or textures size are improved (for example 8192x8192 in DX10 vs 4096x4096 in DX9).
DirectX 10
The arrival of Geometry Shaders, which is located between vertexes and pixels shaders in the pipeline of this API . Their goal is to allow developers to create geometry, a task formerly reserved for PC processor . Thanks to shaders geometry, the developers will be able in particular to improve detail level management , characters, or to improve the extruded shades in some examples.
Radeon HD 2900 XT: unified structure , v2.0!
Microsoft called NVIDIA for the development of the graphics chip for video game console, Xbox, But then it turned to ATI for the development of console graphics chip : next gen. Xenos, Xbox 360 graphics processor , has also unified architecture. ATI proposed the R520 and R580, which started the beginning of unification by uncoupling textures units and treatment pixels pipelines .
Structure unified: why how
By proposing a unified architecture, AMD answers the diversity of game developers . Until now, in the traditional architecture, chip 3D resources were fixed with a certain number of units dedicated to pixels shaders and others for vertexes shaders. With unification, the concept of pixel pipeline disappears purely and simply, and the chip consists of stream processors able to work on any data type , being able to be reconfigured with pixels or vertex shaders. Consequence of this increased flexibility, was a greater computing power available for various 3D programs .
Radeon HD 2900 XT: architecture in detail
Now you know that R600 has a unified architecture. At the head of chip, we finds Processor Command , which will manage the orders of command coming from the graphic driver. Setup Engine prepare the data according to their nature (vertex, pixel or geometry shaders) before subjecting them to the stream processors . Already used in Radeon X1900, this one was passably improved. Let us recall that it acts like a super station to maximize the use of all stream processors by switching data according to the availability of each processor, and this always aim for reducing the latency times and increasing the chip effectiveness . Ultra-Threaded Dispatch Processor has its own memory dedicated for constants and another for shaders instructions witch allow to treat shaders which instructions number is virtually unlimited.
Overall picture : Radeon HD 2900 XT architecture
The unified Structure obliges, the R600 core to be composed from processors more or less independent one from each other. Left DSP (DIGITAL Signal Processor) , are here called stream processors and are gathered according to four large blocks SIMD (Individual Instruction, Multiple Dated) 80 processors each one. Each block SIMD contains actually 16 calculating units, each unit consist of five stream processors .
calculating unit
This architecture super-scalar has IEEE754 certification , and presents large change compared to Radeon X1950 which units operated in vector+scalar mode and could treat only two instructions per clock cycle or 3+1 component, or 4+1 component. Each shader core in R600 can on its side treat up to five scalar instructions MAD (Multiply-Add) in clock cycle or work on five vector components . As a whole, the last AMD card has 320 stream processors , we note that GeForce 8800 GTX has only 128 stream processors .
AMD make us think that NVIDIA GeForce 8800 is seriously exceeded ;-). But here the distribution of stream processors is not the same between AMD and NVIDIA. GeForce 8800 stream processors are completely independent each one from other.
Radeon HD 2900 XT: texture units and ROP
texture unit
As a remainder, R600 texture units are connected to first level memory, witch is connected to the second cache level , about 256 KB, used to cure errors and at the time to obtain a better streaming while readings a not filtered textures. AMD specifies that R600 can work on HDR 64 bits textures seven times faster than Radeon X1000 whereas textures filtering in FP16 is executed at full speed. We also note that high resolution textures support , is required in DirectX 10 specifications as well as the support of new texture format HDR 32 bits with format R:9, G:9, B:9, E:5. AMD in addition indicates the improved quality of anisotropic filtering, mode high quality introduced by Radeon X1000 being now the default mode . As a result no more High Quality box in Catalyst driver. However filtering improvements do not allow ATI to pass in front of NVIDIA GeForce 8 which remains a reference in this case.
filtering AF 16x : 1-) Radeon X1950 XTX, 2-)Radeon HD 2900 XT and 3-) GeForce 8800
DirectX 10 function Stream Out allow allow to recover calculation result without waiting to the end of data in the chip, this one is accessible by each processor and allow in addition the space of storage registers .
Finally our pixels will pass in the ROP, these units load the ultimate operations as colors mixture or anti-aliasing application . Since R300 series , (i.e. since Radeon 9700), the structure of these units had not advanced. R600 is the occasion for AMD to give flat ROP architecture , also known under name Render back end. Whereas GeForce 8800, in its GTX version , has 24 units ROP, R600 or Radeon HD2900 XT has only 16 . It is less than NVIDIA but each unit in theory is able to work on two pixels per clock cycle when GeForce 8800 ROP can work only on two colors or two values Z during the same clock cycle .
The return of TruForm: tessellation unit
AMD released with Radeon HD2900 the second life to its Truform function present on its old chips Radeon 8500. And like Xenos, the graphics chip which animates Xbox 360, R600 has its own tessellation programmable unit . Let us note the tesselation principle , which multiply the geometrical forms on rather simple figure and apply to each polygon a recursive subdivision . In 3D as in geometry, each triangle comprises three tops, and our tessellator will use position and normal, perpendicular vector to the surface of our triangle, to interpolate and generate new tops between vertices\'s (or tops) already existing.
Principle of tesselation
Usually, tessellation can be managed by processor but the presence of dedicated unit makes this process more effective. tessellation unit will be adopted by developers as it is really useful. But here there is one problem, tessellation unit do not form part of DirectX 10 specifications .
More concrete example of the tesselation
Radeon HD 2900 XT: New anti-aliasing
As in each new graphics chip generation , AMD makes improvements to its anti-aliasing functions . In addition to the modes already available in preceding generations as Temporal AA introduced with X800 or Adaptive AA which aims at eliminating crenellation from transparent textures, AMD proposes to us with R600 the CFAA or Custom Filter Anti-Aliasing. The objectives is always the same , to improve quality by reducing the effects . AMD proposes to combine a traditional super-sampling with two new filters without increase in memory usage.
From left to right: Radeon HD 2900 XT AA 4x, CFAA 12x, CFAA 16x, GeForce 8800 AA 4x, CSAA 16x
Concretely, CFAA uses larger number of pixels . AMD uses new algorithms with an adaptive operation: after detecting the edges, pixels filtering present in edge will use more samples than filtering of other pixels. That allow, according to AMD, to perfectly smooth the edges of objects while reducing the swarming of textures and while avoiding making vague certain image details (like text). Functioning with HDR , the CFAA work according to several modes as CFAA 12x and the CFAA 16x.
Activation of the CFAA since pilots CATALYST
A new memory controller … 512 bits really !
R600 memory controller
AMD passes with R600 to the 512 memory system bus . Thanks to this evolution, the memory band-width increases significantly since with simple GDDR3, working at reasonable frequency, AMD has a band-width equal to 106 GB/S. Passage to 512 bits announces: increase in the number of memory chips present with eight channels, a total of 16 chips 32 bits. Note that Radeon HD 2900 XT uses GDDR3 memory and its memory controller is already compatible with GDDR4 .
Radeon HD 2900 XT: AVIVO passes in version 2
AMD benefits from R600 to largely improve its video decompression engine , known as AVIVO. With R600, AMD introduces the UVD or Universal Video decode: a dedicated engine completely independent from the graphic pipeline. In this, AMD approaches NVIDIA and its PureVideo engine which uses exactly the same principle since GeForce 6. . Thus the effectiveness of AVIVO was not at all identical between top-end and low-end Radeon. Present on all R600 range, UVD resembles to mistake with PureVideo engine second generation recently introduced by NVIDIA on its GeForce 8600. However, there are some differences in favor of AMD which, do not deal with decoding algorithm : CABAC used by films in H.264, like NVIDIA, also manages the entropic decoding used VLC employed on HD-DVD. AMD indicates that its UVD, AVIVO HD, can decode high-definition film whose data rate reaches 40 Mbps.
Various decoding stages by AVIVO HD vs PureVideo HD
We checked the contributions of AVIVO HD in terms of processor consumption . For that we employed Ultra PowerDVD 7.3 in its final version with three different chips: GeForce 8800 GTS, Radeon X1950 XTX and Radeon HD 2900 XT. For this last we used the software version provided by AMD, a version slightly adapted to AVIVO HD.
The processor consumption raised with Radeon HD 2900 XT is far from being the best since it has precisely the highest average ! 48% :-) against 34% for GeForce 8800 GTS and 39% with Radeon X1950 XTX…
Radeon HD 2900 XT: HDCP and HDMI
Another update introduced with R600 related to video: the inclusion of HDCP directly in the graphics chip. Radeon HD support HDCP on ets Dual-Link DVI. That allows to the owners of 30 inches screen to profit from HDCP decoding , functionality which is absent in GeForce 8800 :-( . The Radeon HD 2900 has also the native support to HDMI interface with an integrated audio controller . R600 has an audio chip 5.1 used to transmit in HDMI audio data without accompanying your video to require particular wiring as it is currently the case on the majority of graphics card , where it is necessary to connect the card to S/PDIF or to the sound card . This could be a good idea, except that the compatibility of HDMI is limited to 1.2 specifications standard. . Radeon HD 2900 XT support HDMI interface , but the card is not equipped with a physical connector HDMI since AMD made the choice to propose an adapter DVI to HDMI also compatible with audio signals transfer .
Radeon HD 2900 XT: the new amd video chip
Technically, R600, according to data communicated by AMD, compose nearly 700 million transistors witch is a little more than the 680 million transistors in GeForce 8800. Whereas we note that the high end NVIDIA chip is made on 90nm, while AMD use 80nm for its R600. Future Radeon HD 2400 and 2600 will be made on 65nm. Physically, the chip adopts a different presentation from GeForce 8.
Talking about operation frequencies , AMD recommend 740 MHz for the graphics chip and 825 MHz for the 512 MB GDDR 3 memory which accompany it. contrary to GeForce 8, stream processors in Radeon HD 2900 XT operate at the rated graphics chip frequency . This detail could make large performances difference … Also let us note that for the first time on high-end AMD chip , CrossFire is native supported . Like RV570 (Radeon X1950 Pro), CrossFire is integrated directly in the chip. No More need for external cable or Master card as on Radeon X1800 and Radeon X1950.
According to our calculation HD 2900 XT electric consumption is more important and exceeds the recent GeForce 8800 Ultra . Let us recall that the following table show the total system consumption measured during 3DMark 06 test in 2560x1600. the thermal envelope, or TDP, is set to 225 Watts for this new card witch is 96 Watts more than one GeForce 8800 GTS 640 MB… And yes, R600 heats and it heats a lot !
Total system consumption
GeForce 8800 GTX
282 Watts
GeForce 8800 Ultra
311 Watts
Radeon X1950 XTX
280 Watts
Radeon HD 2900 XT
333 Watts
Radeon HD 2900 XT: reference card
For this test, we used AMD reference card as well as a Jetway card. The two card logically shared the same design with 24 cm length and red PCB, witch is larger than the GeForce 8800. The card used the same cooling system with dual slot and also coppers on graphics chip connected by two heat-pipes to a copper radiator. If the fan was rather discrete in 2D, it proves to be particularly noisy in 3D . R
With format PCI-Express 16x, the card lays out has two power supply connectors . The first connector is 8 pins whereas the second is 6 pins.
Reference card AMD Radeon HD 2900 XT
With 512 MB GDDR3 memory , our two card were provided with Hynix 1 ns certified chips . Offering identical frequencies to AMD specifications , with 740 MHz for the graphic core and 825 MHz for the memory, the card were provided with an additional chip Theater 200 for video capture . Radeon HD 2900 XT has two CrossFire catches, and two connectors DVI in addition to mini-DIN connector.
Side bundle finally, Jetway card is accompanied by all necessary cable with two Molex adapters , two adapters DVI/VGA, a CrossFire connector, DVI to HDMI adapter and two cables for analogical video in/out. We also finds in the box a book, driver CD . All Radeon HD 2900 XT, will be delivered with coupon witch allow to obtain Half-Life 2 free - Episode Two and TEAM Fortress 2 .
To test the performances of the last card AMD we have recourse to our usual configuration whose detail appears below:
Motherboard Asus P5W-DH Deluxe (BIOS 2004),
Processor INTEL Core 2 Extreme X6800 (2,93 GHz),
2x 1 GB DDR2 Corsair Twin2X 6400C3,
Hard disk Western DIGITAL Raptor 150 GB Serial-ATA 150
We used Windows Vista , our configuration has the last BIOS and driver available to the date of test. For NVIDIA card we used ForceWare 158.18 , CATALYST 7.4 for Radeon X1000 and Beta 8.37 (CATALYST 7.5) for Radeon HD 2900. We will test here GeForce 8800 GTS 640 MB, GeForce 8800 GTX and GeForce 8800 Ultra and also Radeon X1950 XTX and CrossFire Radeon X1950 XT to compare all them with new Radeon HD 2900 XT.
3DMark 06 - v1.1.0
We starts as always with 3DMark 06 benchmarks . At first place we find GeForce 8800 Ultra and GeForce 8800 GTX whereas Radeon X1950 XT CrossFire show higher performances than Radeon HD 2900 XT, witch finish fourth. Compared to Radeon X1950 XTX, the HD2900 XT is 57% faster in 2560x1600, an advantage which is reduced to 19% vs GeForce 8800 GTS 640 MB, its direct competitor.
Doom 3 - v1.3
Doom 3 does not change the list observed under 3DMark 06, in the first place we have always GeForce 8800 Ultra and GTX and Radeon X1950 XT CrossFire . Radeon HD 2900 XT which interests us today finishes fourth with 19% higher performances than GeForce 8800 GTS 640 MB in 2560x1600. Vs Radeon X1950 XTX, the new-card from AMD is 69% faster in 2560x1600. But here, GeForce 8800 GTX is 18% more powerful.
Far Cry v1.4
The final Far Cry patch 1.4 is not compatible with HDR under Windows Vista :-( . Whereas our various chips seem to be limited by the processor in 1600x1200 and 1920x1200, the passage to 2560x1600 allow to show some result . At the first place figure always the GeForce 8800 Ultra whereas the second place returns to Radeon X1950 XT CrossFire which precedes here the GeForce 8800 GTX. Our Radeon HD 2900 XT is always fourth but deference with GeForce 8800 GTS 640 MB is tightened seriously.
F.E.A.R. - v1.08
F.E.A.R., here used with the soft shadow, the first test allows Radeon HD 2900 XT to finish third (in 2560x1600), in front of the CrossFire system, but this was not enough to reach the GeForce 8800 GTX or the Ultra speed. The advantage of Radeon HD 2900 XT over the GeForce 8800 GTS 640 MB remains moderate: only 10% in 1920x1200. Compared with Radeon X1950 XTX, the Radeon HD 2900 XT appears 51% faster in 1920x1200.
Splinter Cell Chaos Theory v1.05
Splinter Cell confirms the tendency observed in F.E.A.R. the last AMD chip does respectively better than our CrossFire system but it can not reach the GeForce 8800 GTX and Ultra level. Vs GeForce 8800 GTS 640 MB, Radeon HD 2900 XT is 21% faster in 1920x1200, a figure which remains identical in 2560x1600. Vs Radeon X1950 XTX, Radeon HD 2900 XT offers higher performances by 51%.
Half-Life 2 Lost Coast
The last AMD representative is with equality with GeForce 8800 GTX. Vs GeForce 8800 GTS 640 MB, the deference in performances is in favor of Radeon HD 2900 XT witch reaches 41%! Vs Radeon X1950 XTX, Radeon HD 2900 XT is 83% faster in 2560x1600.
Call Of Duty 2 - v1.3
Call Of Duty 2, confirms the good Radeon HD 2900 XT services which is 14% faster than Radeon X1950 XTX in 1920x1200 and 23% faster than GeForce 8800 GTS 640 Mb in the same resolution. The GeForce 8800 GTX and Ultra are largely at the head.
Supreme Commander
If Call Of Duty 2 gave a good indication to Radeon HD 2900 XT, Supreme commander has different result . in 1600x1200 Radeon HD 2900 XT is equivalent to GeForce 8800 GTX, but this last is 19% faster in 2560x1600. Vs Radeon X1950 XTX , the Radeon HD 2900 XT has 30% faster overall .
Company Of Heroes - v1.05
Vs Radeon X1950 XTX, the performances profit obtained reaches 49% in 1920x1200, a figure which remains constant even in 2560x1600.
STALKER v1.0001
Another particularly recent game, In 1920x1200, Radeon HD 2900 XT is beautiful being 76% faster than Radeon X1950 XTX, GeForce 8800 GTS 640 MB remain 7% faster than AMD card.…
Call Of Juarez - DirectX 10
For the first time for several months, we have the ability to test DirectX 10 based engine with Call Juarez game . Here, Radeon HD 2900 XT is 16% faster than GeForce 8800 GTS 640 MB in 1600x1200 but GeForce 8800 Ultra and GeForce 8800 GTX preserve the advantage.
Doom 3 - v1.3 - AA 4x
Here we activate anti-aliasing in Doom 3. First good surprise, Radeon HD 2900 XT is as fast as X1950 XT CrossFire. Vs GeForce 8800 GTS 640 Mb, Radeon HD 2900 XT is 57% faster in 2560x1600.
Call Of Duty 2 - v1.3 - AA 4x & AF
We continue with Call Of Duty 2. And… here a disappointment! Radeon HD 2900 XT is slower here than GeForce 8800 GTS 640 MB, NVIDIA chip is 11 to 13% faster . And vs Radeon X1950 XTX, the Radeon HD 2900 XT show lower performances except in 2560x1600 .
F.E.A.R. v1.08 - AA 4x - AF16x
F.E.A.R really does not manage to support the Radeon HD 2900 XT, once anti-aliasing is activated , The last AMD card is 3% faster than GeForce 8800 GTS 640 MB in 1920x1200 and 12% faster than its predecessor in this resolution. But CrossFire remains 25% faster when GeForce 8800 GTX is 29% more powerful.
Half Life 2 Lost Coast - AA4x - AF16x
Let us finish with Half-Life 2 where we activate anti-aliasing and anisotropic filtering. Radeon HD 2900 XT which is in withdrawal vs GeForce 8800 GTS 640 MB .
Conclusion
After long month , R600 is finally a reality. the first AMD DirectX 10 graphics chip is not killer as the announced GeForce 8 . Technological choices operated by AMD, in particular on the architecture level , make R600, at least in its XT version , is just good to measure in GeForce 8800 GTS, leaving GeForce 8800 GTX and GeForce 8800 Ultra at the head, which is disappointing. Technically AMD architecture is handicapped by an unquestionable conservatism with calculating units , the texture units has a too reduced number , shaders processors functioning at the same chip frequency ( when those are twice faster at NVIDIA ). .
But is most case R600 in not a bad chip !!! Its performance are about higher than GeForce 8800 GTS 640 MB in DirectX 9.0 and OpenGL .
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