NVIDIA’s and AMD’s graphics board partners usually take differing approaches when releasing factory overclocked variants of each company’s respective high-end GPUs. When NVIDIA launches a new part for example, their board partners typically have factory overclocked versions at the ready, and at launch, it’s sometimes easier to find overclocked cards than stock reference models. AMD’s board partners, however, don’t usually take the same approach. When AMD launches a new ATI Radeon, the first batch of cards to hit typically follow the reference design to the letter, and custom, factory overclocked models don’t arrive until some time later.

That’s what happened with the Radeon HD 4870 X2. At launch, just about every Radeon HD 4870 X2 available at retail had the exact same features and specifications. But more recently, a few board partners have introduced factory overclocked variants that take the performance of what is already the fastest graphics card available up a notch. We’ve actually got two of them in house, the Asus EAH4870X2 TOP and the MSI R4870X2-T2D2G-OC, and plan to show you just how much extra performance each has to offer over standard reference cards.
 

ATI Radeon HD 4870 X2

AMD ATI Radeon HD 4800 Series Specifications and Features

956 million transistors on 55nm fabrication process PCI Express 2.0 x16 bus interface 256-bit GDDR3/GDDR5 memory interface Microsoft DirectX 10.1 support Shader Model 4.1 32-bit floating point texture filtering Indexed cube map arrays Independent blend modes per render target Pixel coverage sample masking Read/write multi-sample surfaces with shaders Gather4 texture fetching Unified Superscalar Shader Architecture 800 stream processing units Dynamic load balancing and resource allocation for vertex, geometry, and pixel shaders Common instruction set and texture unit access supported for all types of shaders Dedicated branch execution units and texture address processors 128-bit floating point precision for all operations Command processor for reduced CPU overhead Shader instruction and constant caches Up to 160 texture fetches per clock cycle Up to 128 textures per pixel Fully associative multi-level texture cache design DXTC and 3Dc+ texture compression High resolution texture support (up to 8192 x 8192) Fully associative texture Z/stencil cache designs Double-sided hierarchical Z/stencil buffer Early Z test, Re-Z, Z Range optimization, and Fast Z Clear Lossless Z & stencil compression (up to 128:1) Lossless color compression (up to 8:1) 8 render targets (MRTs) with anti-aliasing support Physics processing support Dynamic Geometry Acceleration High performance vertex cache Programmable tessellation unit Accelerated geometry shader path for geometry amplification Memory read/write cache for improved stream output performance Anti-aliasing features Multi-sample anti-aliasing (2, 4 or 8 samples per pixel) Up to 24x Custom Filter Anti-Aliasing (CFAA) for improved quality Adaptive super-sampling and multi-sampling Gamma correct Super AA (ATI CrossFireX configurations only) All anti-aliasing features compatible with HDR rendering

Texture filtering features 2x/4x/8x/16x high quality adaptive anisotropic filtering modes (up to 128 taps per pixel) 128-bit floating point HDR texture filtering sRGB filtering (gamma/degamma) Percentage Closer Filtering (PCF) Depth & stencil texture (DST) format support Shared exponent HDR (RGBE 9:9:9:5) texture format support OpenGL 2.0 Support   ATI PowerPlay   Advanced power management technology for optimal performance and power savings Performance-on-Demand Constantly monitors GPU activity, dynamically adjusting clocks and voltage based on user scenario Clock and memory speed throttling Voltage switching Dynamic clock gating Central thermal management – on-chip sensor monitors GPU temperature and triggers thermal actions as required Avivo HD Video and Display Platform 2nd generation Unified Video Decoder (UVD 2) Enabling hardware decode acceleration of H.264, VC-1 and MPEG-2 Dual stream playback (or Picture-in-picture) Hardware MPEG-1, and DivX video decode acceleration Motion compensation and IDCT ATI Avivo Video Post Processor New enhanced DVD upconversion to HD new! New automatic and dynamic contrast adjustment new! Color space conversion Chroma subsampling format conversion Horizontal and vertical scaling Gamma correction Advanced vector adaptive per-pixel de-interlacing De-blocking and noise reduction filtering Detail enhancement Inverse telecine (2:2 and 3:2 pull-down correction) Bad edit correction Full score in HQV (SD) and HQV (HD) video quality benchmark   ATI CrossFireX Multi-GPU Technology Scale up rendering performance and image quality with two GPUs Integrated compositing engine High performance dual channel bridge interconnect

The specifications above list the main features and benefits of the RV770 GPU that is the foundation of the Radeon HD 4800 series.  Keep in mind, however, that there are two RV770 GPUs on Radeon HD 4870 X2 cards, each coupled to 1GB of GDDR5 RAM, for a grand total of 2GB of frame buffer memory.  We've gone into detail on the Radeon HD 4870 X2 in the past, so we won't cover the architecture again here, but if you'd like more information about the technologies employed on the Radeon HD 4870 X2, here are a few links to some of our previous coverage:

• ATI Radeon HD 4850 and 4870: RV770 Has Arrived
• ATI Radeon HD 4870 X2 - AMD Back On Top

In our Radeon HD 4850 and 4870 launch article, we write at length about the RV770 GPU and in the 4870 X2 piece we explain how the dual GPUs are implemented on the card.  Those two articles explain many of the more technical details we won't be going into again here.

The Asus EAH4870X2 TOP and MSI R4870X2-T2D2G-OC both look similar to ATI's reference Radeon HD 4870 X2 card, with a few minor aesthetic and technical differences...

    

    
Asus EAH4870X2 TOP

The Asus EAH4870X2 TOP has the same PCB and cooler design as other 4870 X2 cards, but Asus puts their own spin on the cooler with a decal featuring a Asian warrior chick surrounded by some cherry blossoms.  Like other 4870 X2s, the EAH4870X2 TOP features a pair of RV770 GPUs and 2GB of GDDR5 memory (1GB per GPU),but Asus has jacked up the frequencies of both. The EAH4870X2 TOP's GPUs are clocked at 790MHz and its memory comes in at 915MHz, up from 750MHz and 900MHz on stock Radeon HD 4870 X2 cards.  The increases in GPU and memory clocks will give the EAH4870X2 TOP a boost in compute and fillrate performance, and also up peak memory bandwidth.

To compliment the card, Asus includes a handful of accessories with the EAH4870X2 TOP.  Bundled with the card are driver and utility CDs, a leather CD case, a quick setup guide, a CrossFire bridge connector, 6- and 8-pin PCI Express power adapters, an HD component output dongle, and DVI to VGA, DVI to HDMI, and S-Video to composite output adapters.

    

    
MSI R4870X2-T2D2G-OC

MSI's R4870X2-T2D2G-OC also uses the same PCB and coolre as ATI's reference Radeon HD 4870 X2. And like Asus, MSI differentiates their card with a custom decal on the fan shroud and increase clocks.  As we've mentioned, reference Radeon HD 4870 X2 cards have their GPUs clocked at 750MHz and their memory clocked at 900MHz (3600MHz effective), MSI's card however. clocks in with 780MHz GPUs--its memory clock mimics the reference design at 900MHz.

Bundled with the R4870X2-T2D2G-OC are a driver CD, a quick setup guide, a user's manual, a CrossFire bridge connector, an HD component output dongle, and DVI to VGA, DVI to HDMI, and S-Video to composite output adapters.  Unfortunately, no power adapters were to be found.

HOW WE CONFIGURED THE TEST SYSTEMS: We tested all of the graphics cards used in this article on either an Asus nForce 790i SLI Ultra based Striker II Extreme motherboard (NVIDIA GPUs) or an X48 based Asus P5E3 Premium (ATI GPUs) powered by a Core 2 Extreme QX6850 quad-core processor and 2GB of low-latency Corsair RAM. The first thing we did when configuring these test systems was enter their respective BIOSes and set all values to their "optimized" or "high performance" default settings. Then we manually configured the memory timings and disabled any integrated peripherals that wouldn't be put to use. The hard drive was then formatted, and Windows Vista Ultimate was installed. When the installation was complete we fully updated the OS, and installed the latest DX10 redist and various hotfixes, along with the necessary drivers and applications.

HotHardware's Test Systems Intel and NVIDIA Powered

Hardware Used: Core 2 Extreme QX6850 (3GHz) Asus Striker II Extreme (nForce 790i SLI Ultra chipset) Asus P5E3 Premium (X48 Express) Asus EAH4870X2 TOP MSI R4870X2-OC Radeon HD 4870 X2 Radeon HD 4870 Radeon HD 4850 GeForce GTX 260 GeForce GTX 280 2048MB Corsair DDR3-1333 C7 (2 X 1GB) Integrated Audio Integrated Network Western Digital "Raptor" 74GB (10,000RPM - SATA)

Relevant Software: Windows Vista Ultimate SP1 DirectX June 2008 Redist NVIDIA Forceware v178.24 ATI Catalyst v8.10 Benchmarks Used: 3DMark06 v1.0.2 3DMark Vantage v1.0.1 Unreal Tournament 3 v1.2* Crysis v1.2* Half Life 2: Episode 2* Enemy Territory: Quake Wars* * - Custom Benchmark

Futuremark 3DMark06 Synthetic DirectX Gaming

3DMark06

3DMark06 is a synthetic benchmark, designed to simulate DX9-class game titles. This version differs from the earlier 3Dmark05 in a number of ways, and includes not only Shader Model 2.0 tests, but Shader Model 3.0 and HDR tests as well. Some of the assets from 3DMark05 have been re-used, but the scenes are now rendered with much more geometric detail and the shader complexity is vastly increased. Max shader length in 3DMark05 was 96 instructions, while 3DMark06 ups that number to 512. 3DMark06 also employs much more lighting and there is extensive use of soft shadows. With 3DMark06, Futuremark has also updated how the final score is tabulated. In this latest version of the benchmark, SM 2.0 and HDR / SM3.0 tests are weighted and the CPU score is factored into the final tally as well.

So, here's a counterintuitive result.  Because 3DMark06 is CPU bound while running its default test, the factory overclocked Radeon HD 4870 X2 cards can't really spread their wings and perform right on par with the reference card. 

3DMark06's individual shader model 2.0 and 3.0 tests explain what's going on.  The SM 2.0 test shows no improvement on the factory overclocked card due to the CPU limitation, but in the SM 3.0 test, they're able to finally pull ahead of the reference card.

Futuremark 3DMark Vantage Synthetic DirectX Gaming

3DMark Vantage

The latest version of Futuremark's synthetic 3D gaming benchmark, 3DMark Vantage, is specifically bound to Windows Vista-based systems because it uses some advanced visual technologies that are only available with DirectX 10, which y isn't available on previous versions of Windows.  3DMark Vantage isn't simply a port of 3DMark06 to DirectX 10 though.  With this latest version of the benchmark, Futuremark has incorporated two new graphics tests, two new CPU tests, several new feature tests, in addition to support for the latest PC hardware.  We tested the graphics cards here with 3DMark Vantage's Extreme preset option, which uses a resolution of 1,920 x 1,200, with 4X anti-aliasing and 16X anisotropic filtering.

3DMark Vantage showed an unexpected large performance improvement for the factory overclocked Radeon HD 4870 X2 cards over the stock reference model.  The slightly higher core and memory clocks of the Asus card give it a slight edge over MSI's offering. 

The factory overclocked Radeon HD 4870 X2 cards from Asus and MSI showed the largest improvement in 3DMark Vantage's GPU Test 1, with the Asus card once again coming out on top by a slight margin.

Half Life 2: Episode 2 DirectX Gaming Performance

Half Life 2: Episode 2

Thanks to the dedication of hardcore PC gamers and a huge mod-community, the original Half-Life was one of the most successful first person shooters of all time. And courtesy of an updated game engine, gorgeous visuals, and intelligent weapon and level designs, Half Life 2 became just as popular.  Episode 2 - the most recent addition to the franchise - offers a number of visual enhancements including better looking transparent texture anti-aliasing. These tests were run at resolutions of 1,920 x 1,200 and 2,560 x 1,600 with 4X anti-aliasing and 16X anisotropic filtering enabled concurrently.  Color correction and HDR rendering were also enabled in the game engine as well.  We used a custom recorded timedemo to benchmark all cards for these tests.

The reference Radeon HD 4870 X2 and the factory overclocked models from Asus and MSI performed similarly in our Half Life 2: Episode 1 benchmark.  The Asus card once again finished on top, followed by the MSI card, and then the stock reference card.

Unreal Tournament 3 DirectX Gaming Performance

Unreal Tournament 3

If you're a long-time PC gamer, the Unreal Tournament franchise should need no introduction.  UT's fast paced action and over the top weapons have been popular for as long as Epic has been making the games.  For these tests, we used the latest addition to the franchise, Unreal Tournament 3.  The game doesn't have a built-in benchmarking tool, however, so we enlisted the help of FRAPS here.  These tests were run at resolutions of 1,920 x 1,200 and 2,560 x 1,600 with no anti-aliasing or anisotropic filtering enabled, but with the UT3's in game graphical options set to their maximum values, with color correction enabled.

The factory overclocked Radeon HD 4870 X2 cards from Asus and MSI had a 3 - 4 frame per second advantage over the stock reference card in our Unreal Tournament 3 testing.

Enemy Territory: Quake Wars OpenGL Gaming Performance

Enemy Territory: Quake Wars

Enemy Territory: Quake Wars is Based on a radically enhanced version of id's Doom 3 engine and viewed by many as Battlefield 2 meets the Strogg, and then some.  In fact, we'd venture to say that id took EA's team-based warfare genre up a notch or two.  ET: Quake Wars also marks the introduction of John Carmack's "Megatexture" technology that employs large environment and terrain textures that cover vast areas of maps without the need to repeat and tile many smaller textures.  The beauty of megatexture technology is that each unit only takes up a maximum of 8MB of frame buffer memory.  Add to that HDR-like bloom lighting and leading edge shadowing effects and Enemy Territory: Quake Wars looks great, plays well and works high end graphics cards vigorously.  The game was tested with all of its in-game options set to their maximum values with soft particles enabled in addition to 4X anti-aliasing and 16x anisotropic filtering.

The Asus EAH4870X2 TOP and MSI R4870X2-T2DG2-OC both outpaced the stock reference Radeon HD 4870 X2 in our custom Enemy Territory Quake Wars benchmark, by as little as .4 FPS to almost 2 frame per second.  The overclocked cards' increases frequencies gave them the biggest boost in the higher resolution tests.

Crysis v1.2 DirectX 10 Gaming Performance

Crysis

If you're at all into enthusiast computing, the highly anticipated single player, FPS smash-hit Crysis, should require no introduction. Crytek's game engine produces some stunning visuals that are easily the most impressive real-time 3D renderings we've seen on the PC to date.  The engine employs some of the latest techniques in 3D rendering like Parallax Occlusion Mapping, Subsurface Scattering, Motion Blur and Depth-of-Field effects, as well as some of the most impressive use of Shader technology we've seen yet.  In short, for those of you that want to skip the technical jib-jab, Crysis is a beast of a game.  We ran the full game patched to v1.2 with all of its visual options set to 'High' to put a significant load on the graphics cards being tested  A custom demo recorded on the Island level was used throughout testing.

The Asus EAH4870X2 TOP and MSI R4870X2-T2D2G-OC performed a bit better than the stock reference card in our Crysis testing.  The Asus card's higher clocks gave it a slight edge over MSI's offering, but both were faster than the reference card.

Performance Summary: As expected, the Asus EAH4870X2 TOP and MSI R4870X2-T2D2G-OC both outperformed a reference Radeon HD 4870 X2, nearly across the board.  The only instance where the factory overclocked Asus and MSI cards didn't clearly outpace the reference card was in the CPU bound 3DMark06 default test.  In the SM 3.0 / HDR tests build into 3DMark06, however, the Asus and MSI cards came out on the top.  Overall, the Asus EAH4870X2 TOP  finished just ahead of the MSI R4870X2-T2D2G-OC due to its slightly higher GPU and memory frequencies, but the performance deltas were minimal.