It seems like a new year always evokes the feeling of renewed hope and high expectations. And for AMD / ATI at least, 2008 appears to have reinvigorated their graphics division, which appears to be firing on all cylinders at the moment. After a year or so of NVIDIA dominating the high-end graphics space, ATI released the Radeon HD 3870 and HD 3850 cards, which have proved to be competent alternatives at their respective price points. Based on the RV670 GPU, the HD 38xx series has been able to provide similar or better performance than the preceding 2900 XT, while running cooler and consuming less power. That, and their lower price points, makes them much more suitable choice for eventually running CrossFireX configurations somewhere down the road.
Of course, as time passes, board partners will go out and take a popular card and "make it their own" so to speak, typically by modifying the cooling solution and/or bumping up the core and memory speeds. Sapphire, as it turns out, always seems up to the challenge. This article features not one, but two cards that offer differing takes on existing products. One card is built with a completely fanless cooling solution, the other is a pre-overclocked, top-of-the line screamer, complete with vapor-cooling. Two cards, separate target audiences, and Sapphire is out to conquer both.
The first model we're going to show you is the Ultimate HD 3850, the name of which applies more to its silent operating mode than its speed or packaging. It does include 512MB of RAM over the original 3850's 256MB, however, and uses a heat-pipe cooling system which does differentiate it from the competition. The latter card is called the Atomic HD 3870. It features higher speeds, fancy single-slot cooling, and one of the best bundles we have seen in a while - it's a card that definitely warrants some attention. Differences abound, but here's a look at the common specs between the two.
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| ATI Radeon HD 3850 & 3870 |
| Features & Specifications | |
| 666 million transistors on 55nm fabrication process
256bit 8-channel GDDR3/4 memory interface
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
- 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
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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
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As we've covered the architecture of the HD 3850 and HD 3870 in-depth in the past, we won't go into heavy detail in this article. Instead, we suggest you take a look at the following articles for some background information:
ATI Radeon HD 3850 and 3870
ATI Radeon HD 2900 XT
What isn't fully covered there, is that the RV670 is the first GPU that supports DirectX 10.1. This update to the API brings with it better support for multi-sample anti-aliasing, improved shadow filtering capabilities, and better support for multi-core systems. Also, a major addition will be the mandatory use of 32-bit floating point filtering (over the 16-bit filtering found in DX9 and DX10) that will make HDR rendering even more dynamic. With Vista SP1 supposedly only weeks away, it's always good to see hardware out there that will be ready to utilize these new features, even if game developers won't support them right out of the gate.
;)
