
Although the ATI Radeon HD 4850 and HD 4870 were launched nearly four months ago, they are both still exciting cards and we look forward to testing each one that enters our labs. For this article, we have another "TOP" card from ASUS in the form of the EAH4870 TOP, which of course is a factory overclocked Radeon HD 4870. 
Like most other HD 4870s on store shelves, the EAH4870 TOP sports 512MB of GDDR5 memory and a 256-bit memory bus. Additionally, the card features support for DirectX 10.1, Shader Model 4.1, and CrossFireX multi-GPU technology. What differentiates the EAH4870 TOP from most other 4870s is its factory overclock: the core clock pushes pixels at 815 MHz (ATI's reference spec is 750 MHz) while the memory is set to 925 MHz (ATI reference is 900 MHz). 
 
 
That is a decent overclock, especially for the core, and we were excited to see how this card would perform compared to a reference Radeon HD 4870, Radeon HD 4850, GeForce GTX 260 and GeForce 9800 GTX. Before we get into the results of our testing, let's take a closer look at the Radeon HD 4800 Series specifications and features and then take a tour of the EAH4870 TOP. 
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| AMD ATI Radeon HD 4800 Series |  
| Specifications and Features |  | 
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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 
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
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 gatingCentral thermal management – on-chip sensor monitors GPU temperature and triggers thermal actions as required 
ATI 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 benchmarks
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 DVI display outputs  
Primary supports 18-, 24-, and 30-bit digital displays at all resolutions up to 1920x1200 (single-link DVI) or 2560x1600 (dual-link DVI) 
Secondary supports 18-, 24-, and 30-bit digital displays at all resolutions up to 1920x1200 (single-link DVI only) 
Each includes a dual-link HDCP encoder with on-chip key storage for high resolution playback of protected content4
Two integrated 400MHz 30-bit RAMDACs  
Each supports analog displays connected by VGA at all resolutions up to 2048x15363
DisplayPort output support  
Supports 24- and 30-bit displays at all resolutions up to 2560x16003
HDMI output support  
Supports all display resolutions up to 1920x1080 
Integrated HD audio controller with up to 2 channel 48 kHz stereo or multi-channel (7.1) AC3 enabling a plug-and-play cable-less audio solution
Integrated AMD Xilleon HDTV encoder  
Provides high quality analog TV output (component/S-video/composite) 
Supports SDTV and HDTV resolutions 
Underscan and overscan compensation 
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
ATI CrossFireX Multi-GPU Technology  
Scale up rendering performance and image quality with two GPUs 
Integrated compositing engine 
High performance dual channel bridge interconnect 
 
 ASUS packs the EAH4870 TOP in a simple yet nicely designed orange and black box that features a female warrior on the right side. ASUS's warrior choice is interesting to say the least, and she actually shows up again on the cooler. When we opened up the main, external box, we were pleasantly surprised by the black boxes that greeted us. Each black box has a gold ASUS logo stamped on it. Ultimately it is of course irrelevant if the card doesn't perform well (and even if it does), but this is easily one of the best video card packaging presentations we've seen in a long time.  The bundle included with the EAH4870 TOP, however, is more practical than exciting. ASUS throws in a quick setup installation guide, a CrossFire connector, an ASUS utility CD, a VGA driver CD, a DVI-to-VGA adapter, a DVI-to-HDMI adapter, an HDTV-out cable, a PCI Express power cable, and an ASUS-branded leather mouse pad.
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