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Radeon HD 3870 X2 Round-Up: Asus, HIS
Date: Feb 25, 2008
Author: Marco Chiappetta
Introduction and Specifications

A few short weeks ago, AMD unleashed the dual-GPU powered ATI Radeon HD 3870 X2, which marked the company’s re-entry into the ultra high-end desktop graphics card space that had been dominated by NVIDIA since the introduction of the GeForce 8800 series.   As we mentioned in our launch coverage, the Radeon HD 3870 X2 utilizes a pair of R670 graphics processors working together on a single PCB, for what is essentially a single-card CrossFire configuration.
AMD’s reference design called for two R670 GPUs clocked at 825MHz with 1GB (512MB per GPU) of 900MHz frame buffer memory.   Leading up to the launch, representative from AMD had mentioned, however, that some of their board partners were likely to releases X2 cards that differed from the reference design.  With that in mind, we were eager to get our hands on some retail-ready Radeon HD 3870 X2 cards to truly see what AMD’s board partners had in store.

In this article, we’ll be taking a look at three Radeon HD 3870 X2 cards, two from Asus and one from HIS.  A pair of the cards are much like AMD’s reference design, but one of them is hardly recognizable as a Radeon HD 3870 X2 – at least not at first glance.

ATI Radeon HD 3870 X2 Reference Design

ATI Radeon HD 3870 X2
Features & Specifications

666 million transistors on 55nm fabrication process (x2)

256bit 8-channel GDDR3/4 memory interface (x2)

Ring Bus Memory Controller

  • Fully distributed design with 512-bit internal ring bus for memory reads and writes
  • Optimized for high performance HDR (High Dynamic Range) rendering at high display resolutions

Unified Superscalar Shader Architecture

  • 320 stream processing units (x2)
    • 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 80 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

Full support for Microsoft DirectX 10 / 10.1 

  • Shader Model 4.0
  • Geometry Shaders
  • Stream Output
  • Integer and Bitwise Operations
  • Alpha to Coverage
  • Constant Buffers
  • State Objects
  • Texture Arrays

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 (up to 8 samples per pixel)
  • Up to 24x Custom Filter Anti-Aliasing (CFAA) for improved quality
  • Adaptive super-sampling and multi-sampling
  • Temporal anti-aliasing
  • Gamma correct
  • Super AA (CrossFire configurations only)
  • All anti-aliasing features compatible with HDR rendering

CrossFire Multi-GPU Technology

  • Scale up rendering performance and image quality with 2 or more GPUs
  • Integrated compositing engine
  • High performance dual channel interconnect
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
  • Bicubic 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

ATI Avivo HD Video and Display Platform

  • Two independent display controllers
    • Drive two displays simultaneously with independent resolutions, refresh rates, color controls and video overlays for each display
    • Full 30-bit display processing
    • Programmable piecewise linear gamma correction, color correction, and color space conversion
    • Spatial/temporal dithering provides 30-bit color quality on 24-bit and 18-bit displays
    • High quality pre- and post-scaling engines, with underscan support for all display outputs
    • Content-adaptive de-flicker filtering for interlaced displays
    • Fast, glitch-free mode switching
    • Hardware cursor
  • Two integrated dual-link DVI display outputs
    • Each supports 18-, 24-, and 30-bit digital displays at all resolutions up to 1920x1200 (single-link DVI) or 2560x1600 (dual-link DVI)
    • Each includes a dual-link HDCP encoder with on-chip key storage for high resolution playback of protected content
  • Two integrated 400 MHz 30-bit RAMDACs
    • Each supports analog displays connected by VGA at all resolutions up to 2048x1536
  • HDMI output support
    • Supports all display resolutions up to 1920x1080
    • Integrated HD audio controller with multi-channel (5.1) AC3 support, enabling a plug-and-play cable-less audio solution
  • Integrated Xilleon HDTV encoder
    • Provides high quality analog TV output (component / S-video / composite)
    • Supports SDTV and HDTV resolutions
    • Underscan and overscan compensation
  • HD decode for H.264/AVC, VC-1, DivX and MPEG-2 video formats
    • Flawless DVD, HD DVD, and Blu-Ray playback
    • Motion compensation and IDCT (Inverse Discrete Cosine Transformation)
  • HD video processing
    • Advanced vector adaptive per-pixel de-interlacing
    • De-blocking and noise reduction filtering
    • Edge enhancement
    • Inverse telecine (2:2 and 3:2 pull-down correction)
    • Bad edit correction
    • High fidelity gamma correction, color correction, color space conversion, and scaling
  • MPEG-2, MPEG-4, DivX, WMV9, VC-1, and H.264/AVC encoding and transcoding
  • Seamless integration of pixel shaders with video in real time
  • VGA mode support on all display outputs

PCI Express 2.0 x16 bus interface

OpenGL 2.0 support



Above are the complete specifications and feature-set of the Radeon HD 3870 X2.  Due to the fact that we’ve already covered the underlying technology employed in the R670 GPUs powering the X2, and have already detailed the reference card’s features and performance, we’re not going to rehash those details again here.   If you’re unfamiliar with the Radeon HD 3870 X2, however, and would like more details we suggest checking out a couple of our recent articles.  In our Radeon HD 3870 and 3850 coverage, we discuss the R670 GPU in depth.  And in our Radeon HD 3870 X2 launch article, we cover the card’s main features and inner workings.  If you check out those two pieces, they’ll get you up to speed.
A Close-Up Look At The Cards

The first card we’re going to show you here is the Asus EAH3870 X2 1GB.  As you’ll see, the card is much like AMD’s reference design, save for a couple of minor details...


 Asus EAH3870 X2 1GB

The Asus EAH3870 X2 1GB has a custom decal affixed to its fan shroud, and it is bundled with a leather CD / DVD case, a driver and utility disk, and a second utility disk that includes a number of proprietary Asus applications in addition to a copy of 3DMark06.  The card’s bundle also includes two DVI-to-VGA adapters, a DVI to HDMI (with audio) adapter, a CrossFire bridge connector, a dual Molex-to-6-Pin PCI Express power adapter, a HD component output dongle, and a full version of the current, DX10 game Company of Heroes: Opposing Fronts.  Although not as popular as a game like Crysis or CoD4, the inclusion of CoH:OF is welcome considering the card’s price.

We should note that the Asus EAH3870 X2 1GB is not factory overclocked.  Its GPUs are clocked at 825MHz and its memory is clocked at 900MHz (1.8GHz DDR), just like AMD’s reference design.  And the card carried a carries a 3-year warranty.



HIS Radeon HD 3870 X2

The HIS Radeon HD 3870 X2 is also based on ATI’s reference design (and is clocked the same too), sans the large decal on the fan shroud.  With this setup, it’s easy to see the dual aluminum / copper heatsinks affixed to the GPUs and the aluminum heatsinks fins in the center that cover the on-board PCI Express fan-out switch.

HIS includes a couple of noteworthy accessories with their Radeon HD 3870 X2 card.  Along with a DVI to HDMI adapter, dual DVI to VGA adapters, a CrossFire bridge connector, and HD component output dongle, the card ships with a driver CD, a case badge, and a certificate for Valve’s Black Box gaming bundle, which is comprised of Half Life: Episode 2, Portal, and Team Fortress 2.  Also included is a handy pen-screwdriver branded with a large HIS logo.



 Asus EAH3870 X2 1GB TOP

Although its box looks similar, the Asus EAH3870X2 1GB TOP is a different animal than the “non-TOP” version pictured at the top of the page.  The Asus EAH3870X2 1GB TOP differs from AMD’s reference design in a number of meaningful ways.   First of all, the cooling apparatus used on the card is completely different.  Asus’ design employs a pair of heatsinks with heat-pipes with dual, dedicated fans – one for each GPU.  We found the cooling apparatus to work well too.  Whereas the GPUs on a reference 3870 X2 typically idled at about 55ºC and hit about 85ºC under load, this dual-fan solution kept the GPUs at about 52ºC while idling at 80ºC under load.  And it does its job quietly.

The Asus EAH3870X2 1GB TOP is also factory overclocked.  The GPUs on the card are clocked at 850MHz and the memory it cranked up to 950MHz (1.9GHz DDR).  We should also note that Asus uses .8ns Hynix GDDR3 RAM on the card, which is rated for up to 1200MHz, so there should be some headroom available for the overclockers out there.  Finally, the EAH3870X2 1GB TOP differs from the reference design in that is has four dual-link DVI outputs.  What Asus has done, is utilize both of the outputs on each GPU, so the EAH3870X2 1GB TOP works just like a pair of standard Radeon HD 3870 X2 cards running in CrossFire mode.

Our Test Systems and 3DMark06

HOW WE CONFIGURED THE TEST SYSTEMS: We tested all of the graphics cards used in this article on either an EVGA nForce 680i SLI motherboard (NVIDIA GPUs) or an Asus P5E3 Deluxe (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 the test systems was enter their respective BIOSes and set all values to their "optimized" or "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.

The HotHardware Test System

Core 2 Extreme Powered


Motherboard -

Video Cards -

Memory -

Audio -

Hard Drive

Hardware Used:
Core 2 Extreme QX6850 (3GHz) 

EVGA nForce 680i SLI
nForce 680i SLI chipset

Asus P5E3 Deluxe
X38 Express 

Asus EAH3870 X2 1GB
Asus EAX3870 X2 1GB TOP
HIS Radeon HD 3870 X2
ATI Radeon HD 3870 X2
Radeon HD 3870 (x 2)

Radeon HD 3870
GeForce 8800 GTX

2048MB Corsair PC2-6400C3
2 X 1GB
2048MB Corsair DDR3-1333 C7
2 X 1GB

Integrated on board

Western Digital "Raptor"

74GB - 10,000RPM - SATA

OS - 

DirectX -

Video Drivers

Synthetic (DX) -
DirectX -
DirectX -
DirectX -
DirectX -
OpenGL -

Relevant Software:

Windows Vista Ultimate

DirectX 10

NVIDIA Forceware v169.09/v169.28
ATI Catalyst Bets v8.451

Benchmarks Used:
3DMark06 v1.0.2
Company of Heros - DX10
Crysis - DX10
Half Life 2: Episode 2*
Enemy Territory: Quake Wars*

* - Custom Test
(HH Exclusive demo)

Performance Comparisons with 3DMark06 v1.0.2
Details: www.futuremark.com/products/3dmark06

3DMark06 is the most recent addition to the 3DMark franchise. This version differs from 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 as well. 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.

Our 3DMark06 results were interesting to say the least.  The factory-overclocked EAH3870 X2 1GB TOP put up the best overall score amongst the X2 cards, but by a very small margin.  It turned out that the card's Shader Model 2.0 test result was actually coming in a bit lower than the other X2s, but its Shader Model 3.0 / HDR results were marginally higher. These were repeatable results, although unexpected considering the card's higher-clocked GPUs.

Half Life 2: Episode 2

Performance Comparisons with Half-Life 2: Episode 2

Details: www.half-life2.com

Half Life 2:

Episode 2

Thanks to the dedication of hardcore PC gamers and a huge mod-community, the original Half-Life became one of the most successful first person shooters of all time.  And thanks to an updated game engine, gorgeous visual, and intelligent weapon and level design, Half Life 2 became just as popular.  Episode 2 offers a number of visual enhancements including better looking transparent texture anti-aliasing. These tests were run at resolutions of 1,280 x 1,024, 1,600 x 1,200 and 1,920 x 1,200 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 file to benchmark all cards in this test.

All of the Radeon HD 3870 X2 cards performed as expected in our custom Half Life 2: Episode 2 benchmark.  The Asus EAH3870 X2 1GB TOP came out, well on top, thanks to its higher clocked GPU and memory.  The other X2 cards, however, performed right on top of eachother, which was to be expected considering they all have the same features and specifications.

Company of Heroes

Performance Comparisons with Company of Heroes

Details: www.companyofheroesgame.com

Company of Heroes

Relic Entertainment's World War II era real-time strategy game Company of Heroes was originally released as a DirectX 9 title for Windows.  But recent upates to the game have incorporated support for new DirectX 10 features that improve image quality and enhance the game's finer graphical details.  The game features a built-in performance test which which we used to attain the results below. Our Company of Heroes tests were run at resolutions of 1,280 x 1,024, 1,600 x 1,200 and 1920 x 1200 with 4X anti-aliasing and all of the game's image-quality related options set to their maximum values.

The Asus EAH3870 X2 1GB TOP's increased GPU and memory clock speeds gave it a small edge in the Company of Heroes DX10 benchmark.  At the lower resolutions, all of the Radeon HD 3870 X2 cards performed similarly, but once the resolution was increased the EAH3870 X2 1GB TOP was able to pull ahead by a couple of frames per second.

Enemy Territory: Quake Wars

Performance Comparisons with ET: Quake Wars

Details: www.enemyterritory.com

Enemy Territory: 
Quake Wars

Enemy Territory: Quake Wars is Based on id's radically enhanced 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 extremely large environment and terrain textures that cover vast areas of maps without the need to repeat and tile many small 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 results from our custom Enemy Territory: Quake Wars benchmark essentially mirror those from CoH on the previous page.  The factory-overclocked EAH3870 X2 1GB TOP came out slightly ahead of the other Radeon HD 3870 X2 cards, with the most pronouced victory (relatively speaking) coming at the highest resolution.

Crysis Performance

Performance Comparisons with Crysis

Details: www.ea.com/crysis


If you're at all into enthusiast computing, the highly anticipated single player demo of the hot, new, upcoming FPS smash-hit Crysis, should require no introduction. Crytek's game engine visuals are easily the most impressive real-time 3D renderings we've seen on the computer screen 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 HOT.  We ran the SP demo with all of the game's visual options set to 'High' to put a significant load on the graphics cards being tested.

We saw more of the same in the Crysis GPU benchmark.  In this test, the EAH3870 X2 1GB TOP once again finishes slightly ahead of the other Radeon HD 3870 X2 cards at all resolutions, with the largest margin of victory coming at 1920 x 1200.

Our Summary and Conclusion

Performance Summary: All of the Radeon HD 3870 X2 cards we’ve looked at in this round-up performed as expected.  The Asus EAH3870 X2 1GB and HIS Radeon HD 3870 X2 performed similarly to each other and to AMD’s reference design, which was to be expected considering all of the cards have the same features and specifications.  The Asus EAH3870 X2 1GB TOP, however, had a slight advantage in all of the benchmarks (with the exception of the anomaly in 3DMark06’s SM2.0 test) thanks to its higher core GPU and memory clock frequencies.

Asus EAH3870 X2 1GB:
The Asus EAH3870 X2 1GB is a solid offering from Asus.  It doesn’t differ from AMD’s reference design, save for its custom fan-shroud decal and accessory bundle, but neither will most other X2 cards.  Asus does throw in a full version game with the card, Company of Heroes: Opposoing Forces, that sweetens the deal somewhat.  In addition, the company’s reputation is second to none, which is sure to entice some consumers.  This card is difficult to find for sale at the moment, but we have seen it for sale for $449.  At that price, the Asus EAH3870 X2 1G is right in-line with other X2 offerings despite the inclusion of CoH and some other value added accessories.

  • Great Performance
  • Decent Bundle
  • Can't Find It For Sale Yet

HIS Radeon HD 3870 X2:

Form a technical standpoint, the HIS Radeon HD 3870 X2 is virtually identical to the Asus EAH3870 X2.  It offers the same features and performance and even looks almost the same, minus a decal or two.  HIS’ bundle is a little better than Asus’ though.  In our opinion, Valve’s Black Box gaming bundle is more valuable than a copy of CoH.  HIS’s card also comes in at $449, like other Radeon HD 3870 X2s, so there’s no price differentiation to speak of.  Overall, the HIS Radeon HD 3870 X2 is nice, but it doesn’t’ stand out in any meaningful way in light of other Radeon HD 3870 X2 cards.

  • Great Performance
  • Solid Bundle
  • No Stand-Out Features

Asus EAH3870 X2 1GB TOP:
As long as the Asus EAH3870 X2 1GB TOP isn’t prohibitively expensive in light of other Radeon HD 3870 X2 cards, we think it will be “the” X2 to own.  The Asus EAH3870 X2 1GB TOP has a pretty good bundle, and a feature set that is second to none.  Factory overclocked for increased performance? Check.  Quad DVI-outputs?  Check.  A custom, quiet cooling solution?  Check.  In terms of features and performance, the Asus EAH3870 X2 1GB TOP is the most powerful and feature rich Radeon out there currently.  We just can’t find it for sale anywhere just yet.  Hopefully it’ll be available soon and at a competitive price.

Update: We've heard some reports of instability and strange driver behavior with the Asus EAH3870 X2 1GB TOP and are looking into them further.  So far, we've tried our sample on an X38 and a 790FX mobo with 32-bit Windows Vista and it is working fine, however.  We'll post more information about this issue when we have it.

Update: We've done some more testing with the EAH3870X2 1GB TOP and had no trouble in our typical testing environment (Vista 32-bit).  We should note, however, that we also tried the card briefly under 64-bit Vista with a Phenom / 790FX combo, and did experience a D3D error with 3DMark06.  Asus has also gotten back to us and said verbatim that there is a, "delay in getting the cards out to the channel. We still plan to have the SKUs, but cannot give you a firm availability date. The problem is that allocation on the 3870 is tight in general." 

Update: Asus has set the price of the EAH3870X2 1GB TOP at $479, which makes the card well worth the upgrade from a standard X2 in our opinion.  They should be hitting store shelves soon.

  • Quiet, Custom Cooler
  • Factory Overclocked
  • Quad DVI Outputs
  • Great Performance
  • Decent Performance
  • Unsure of Pricing
  • Not Available Yet

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