R680 Has Landed: ATI Radeon HD 3870 X2 - HotHardware

R680 Has Landed: ATI Radeon HD 3870 X2

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When AMD released the Radeon HD 2900 XT in May of last year, we were left with a bitter taste in our mouths.  Not because the product was all that bad, but because it seemed AMD was content to leave NVIDIA uncontested at the high-end of the 3D graphics card market.  If you remember, when the Radeon HD 2900 XT launched AMD had targeted the mid-range GeForce 8800 GTS, and not NVIDIA’s high-end 8800 GTX or Ultra.  It seemed as if AMD just didn’t want to be in the fight for 3D graphics supremacy any longer and enthusiasts like yourselves, who seek nothing but the highest performing products, were left with only a single option.

Thankfully things have changed in the last few months.  After the R600 shipped, AMD’s engineers went right back to work.  And in November AMD released the Radeon HD 3800 series of products, which were based on an updated GPU design that performed much like the R600, but with more moderate power and thermal characteristics.  The new GPU, formerly codenamed RV670, still wasn’t quite as fast as NVIDIA’s higher-end offerings, but its low power profile gave AMD the ability to engineer the product we’ll be showcasing here today, the Radeon HD 3870 X2.

The Radeon HD 3870 X2 was codenamed R680 throughout its development.  Although that codename implies the card is powered by a new GPU, it is not.  The Radeon HD 3870 X2 is instead powered by a pair of RV670 GPUs linked together on a single PCB by a PCI Express fan-out switch.  In essence, the Radeon HD 3870 X2 is “CrossFire on a card”.  Take a look...

ATI Radeon HD 3870 X2

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



ATI Really Wanted To Protect This Baby

To get more familiar with AMD's new ATI Radeon HD 3870 X2, the company's previous GPU architectures, and their key features, we recommend you read a few recent articles we've posted here at HotHardware. The Radeon HD 3870 X2's pair of RV670 GPUs are derived from of the R600, and as such they have a number of key features in common that we've already covered in much greater detail that we will here today. The articles we suggest you check out include:

If you haven't already done so, we recommend scanning through our Radeon HD 3800 and 2900 series coverage, our CrossFire Multi-GPU technology preview, and the Radeon X1950 Pro with Native CrossFire article. In those four pieces, we cover a large number of the features offered by the new Radeon HD 3870 X2 and explain many of the features of DirectX 10 and 10.1. We recommended reading these articles because there is quite a bit of background information in them that'll make it easier to fully digest what we're going to showcase here today.

Article Index:

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You guys are awesome at missing the mark. 

To phresh:

What makes you an authority? Do you have any legitimate credentials?

You come off like you know a page more than the book, have you ever built a system... if so, how many?

Do you have any expirience bench testing high end machines comparatively or running a tech website?

Do you consider your critiques constructive criticism? If not then what is your agenda?

To the admins:

I've gathered that you guys have a pretty "thick skin" for the most part, but I can't help feeling as though phresh is willfully condescending and also can't help feeling a bit aggitated by it.

To the HH forum community:

You guys may feel like I'm overreacting and wasting my time by questioning this individual, but I respect HotHardware and trust their reviews implicitly!

BTW: If you think my reaction was spawned by just 1 post, read his other 2!


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To phresh:

What makes you an authority?

Never claimed to be an authority. I'm just a dude that thinks critically and enjoys flaming forums. 



Do you have any legitamate credentials?

I can spell legitimate, does that count? 


You come off like you know a page more than the book, have you ever built a system... if so, how many?

No, I just run eMachines. lol. Really though, approaching 50 or so over the past decade. 


Do you have any expirience bench testing high end machines comparatively or running a tech website?

Bench testing yes, did a lot getting my q6600 to 3.4 stable on air without too many volts. Tech website, nope.


Do you consider your critiques constructive criticism? If not then what is your agenda?

Yes and I also enjoy being condescending, bite me.  My agenda is simply to point out things that don't make sense and have a bit of fun along the way.




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IMO you are misinformed and childish. I hope that if you continue to post here that you will step up your maturity and present your oppinion without disrespecting the people that run this site.



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 And I think you lack any significant point and suck at spelling. Let's fight about it.

 The fact remains that no one here has properly addressed the issues I brought up. Pure fail.

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We don't flame here, find another forum to disrespect.

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I'll disagree with your assessment that this was a "terrible" review, but I see where you're coming from. The reason I don't test SLI is two-fold - 1) I compared single-cards throughout the benchmarks, and only included 3870 CrossFire as a reference point and 2) NVIDIA's 8800 GTX is the closes price-match to the X2.

HotHardware readers know that NVIDIA cards can be run in SLI mode, and there are a TON of SLI benchmarks on the site for all to see. This isn't "imsortaintopchardwareanddontknowmuch.com".

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Everyone is making such a big deal about it but I think the performance ended up exactly where I thought it would.. basically 8800GTX ish performance with the right driver support of course. I think this card bought AMD some time but their next GPU had better really bring the goods or its gona be another long year for AMD. The price performance of this card is really good.. I think if it can be aquired for 399 ish then it would be a real deal. I would like to see a few more games thrown in when you guys get the time. I would also like to aquire the HIS overclocked turbo model instead of the reference design. My 2 cents.

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Hi All, That's pretty much what I thought as well. New egg however has the cards in stock for this price though. http://www.newegg.com/Store/SubCategory.aspx?SubCategory=48&name=Video-Cards

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 Hi there,

I have a 17 inch LCD monitor 1280*1024 32bit, Intel Core 2 Duo E6300 @ 3.262GHz 466FSB ORTHOS,PRIME,OCCT,SANDRA,AND OTHER FULLY STABLE (1.86GHz Default) with Gigabyte GA-P35-DQ6 Motherboard (Rev. X.X WITH F7 BIOS) with 2GB Kingston Hyper-X 800MHz Memory modules in Dual Channel Mode (128bit - 64bit*2).I'm using ATI GFX-Cards FOREVER and the reason is because i don't know what the Bench sites are saying or doing but every time that i was trust any of the benchmarks i was pissed off because is like they are saying lies to me at least.Finally i want to make something about the ATI HD3870 clear and not for the ATI HD3870 X2 is that in any game i'm playing the frames are about 60F.P.S.(Frames Per Second) and up, not at least in any time of the game drops below of that at ALL FULL GRAPHICS and all Details Cranked Up - AA16X,HDR and so on...... and something else those 55nm babes and not 65nm are so easy overclockable ~1000MHz+++ core (stock cooling- within VGA BIOS modifications).

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Hi All

I agree with you Flyin. I think that HotHardware's approach to benchmarking is the right way to go. The creation of their own time demo addresses the canned benchmark concern, while at the same time giving you a real world experience.

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