The Radeon 4850 took the world by storm not too long ago late last month and the ATI Radeon HD 4870 was quick to follow. Unfortunately our review sample was a few days late and the review of two new AMD processors happened the Tuesday after we received them so we're a little late to the review but still here with helpful information.

The RV770 is manufactured on a 55nm manufacturing process as was the Radeon 3000 series and the 4870 sports about 965 million transistors. The card doesn't add much in way of new features from the 3870 still supporting DX 10.1, CSAA, Crossfire, and more although one new addition is the inclusion of the next-gen video decoder, the UVD2. The 4870 sports a 750MHz core speed from the 625MHz of the 4850, it still boasts 512MB of RAM but this time it's super high bandwidth GDDR5 as opposed to GDDR3 which it uses to over come the 256-bit memory interface. The 4870 has a 160W TDP and requires two 6-pin PCI-Express connectors in order to function and thus with SLI you'll need 4 6-pin PCI-E power adapters so keep in mind if you do go for this card. It is also dual slot and doesn't get quite as hot as the Radeon HD 4850 but definitely gets up there. Perhaps most impressive of the 4000 series is that the number of stream processors has bolted to 800 from 320 from the 3000 and 2000 series more than doubling overall and allowing for huge gains.

The MSRP for the Radeon HD 4870 is $299 and you can get it for at Amazon and the Radeon HD 4850 for $192.

# 956 million transistors on 55nm fabrication process
# PCI Express 2.0 x16 bus interface
# 256-bit GDDR3/4/5 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
o Dynamic load balancing and resource allocation for vertex, geometry, and pixel shaders
o Common instruction set and texture unit access supported for all types of shaders
o 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)
* Up to 8 render targets (MRTs) with anti-aliasing
* Accelerated physics processing

# 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 Avivo™ HD Video and Display Platform6

* Unified Video Decoder 2 (UVD 2) for H.264/AVC, VC-1, and MPEG-2 video formats
o High definition (HD) playback of Blu-ray and HD DVD video
o Dual stream (HD+SD) playback support
o DirectX Video Acceleration 1.0 & 2.0 support
o Support for BD-Live certified applications
* Hardware DivX and MPEG-1 video decode acceleration
* Accelerated video transcoding & encoding for H.264 and MPEG-2 formats
* ATI Avivo Video Post Processor6
o Color space conversion
o Chroma subsampling format conversion
o Horizontal and vertical scaling
o Gamma correction
o Advanced vector adaptive per-pixel de-interlacing
o De-blocking and noise reduction filtering
o Detail enhancement
o Color vibrance and flesh tone correction
o Inverse telecine (2:2 and 3:2 pull-down correction)
o Bad edit correction
o Enhanced DVD upscaling (SD to HD)
o Automatic dynamic contrast adjustment
* Two independent display controllers
o Drive two displays simultaneously with independent resolutions, refresh rates, color controls and video overlays for each display
o Full 30-bit display processing
o Programmable piecewise linear gamma correction, color correction, and color space conversion
o Spatial/temporal dithering provides 30-bit color quality on 24-bit and 18-bit displays
o High quality pre- and post-scaling engines, with underscan support for all display outputs
o Content-adaptive de-flicker filtering for interlaced displays
o Fast, glitch-free mode switching
o Hardware cursor
* Two integrated dual-link DVI display outputs
o Each supports 18-, 24-, and 30-bit digital displays at all resolutions up to 1920x1200 (single-link DVI) or 2560x1600 (dual-link DVI)2
o Each includes a dual-link HDCP encoder with on-chip key storage for high resolution playback of protected content3
* Two integrated 400 MHz 30-bit RAMDACs
o Each supports analog displays connected by VGA at all resolutions up to 2048x15362
* DisplayPort output support
o 24- and 30-bit displays at all resolutions up to 2560x16002
* HDMI output support
o All display resolutions up to 1920x10802
o Integrated HD audio controller with support for stereo and multi-channel (up to 7.1) audio formats, including AC-3, AAC, DTS, DTS-HD & Dolby True-HD4, enabling a plug-and-play audio solution over HDMI
* Integrated AMD Xilleon™ HDTV encoder
o Provides high quality analog TV output (component/S-video/composite)
o Supports SDTV and HDTV resolutions
o Underscan and overscan compensation
* Seamless integration of pixel shaders with video in real time
* VGA mode support on all display outputs

# ATI PowerPlay™ Technology5

* Advanced power management technology for optimal performance and power savings
* Performance-on-Demand
o Constantly monitors GPU activity, dynamically adjusting clocks and voltage based on user scenario
o Clock and memory speed throttling
o Voltage switching
o Dynamic clock gating
o Central thermal management – on-chip sensor monitors GPU temperature and triggers thermal actions as required

# ATI CrossFireX™ Multi-GPU Technology

* Scale up rendering performance and image quality with two, three, or four GPUs
* Integrated compositing engine
* High performance dual channel bridge interconnect1

Our first impression of this card in the limited time we had is that it is amazing ATI put so much power into a single slot card. It does appear to run very hot, at around 155 degrees Fahrenheit by our initial tests but it is a single slot card and we can say the fastest single slot card on the market. A bigger heatsink/fan could have helped but it seems to be quite a powerful package for an amazing price.

Here is our current test system.

Our test OS was Windows Vista Ultimate SP1 with Nvidia's 175.19 of Forceware drivers and ATI Catalyst 8.6 Hotfix. All the latest software revisions were used in our testing.

Crysis seems to be one of the last games that still favors Nvidia at this time with the 9800 GTX cards just coming out on top. Hopefully with some more optimizations ATI will be able to pull out and take the lead in Crytek's very advanced shooter.

Unreal Tournament 3 is the most popular graphics engine in use today and something we thus must test. Only at the highest 2560x1600 resolution does the 4870 in Crossfire seem to matter coming out on top by a number of frames per second here.

Quake Wars is one of the last Open GL games on the market and may not have much of a life longer as an API for games but for now it's something we'll be testing. We re-did some testing from our 4850 review and here we see ATI in the lead with id software's game, one of the few times we could say that but it is definitely the case now.

Age of Conan is easily one of the most popular new games on the PC and the new 4000 series of cards edge out Nvidia at 2560x1600. 4870 Crossfire is one exception we ran across an anomaly there where performance was simply unplayable though 4850 Crossfire works fine. Both SLI and Crossfire see huge gains here except for the 4870 anomaly.

In 3DMark 2006 the 4870 just edges out the 9800 GTX.

Now let's took a look at power consumption. For load we ran only 3DMark Vantage feature tests that stressed the graphics card only.