Test: HIS HD 4890 iCooler x4

Innovation/Teknologi

HD4890 GPU'en blev frigivet af AMD/ATI den 2. april 2009. AMD/ATI GPU'en har kodenavn "RV790" og er bygget på 55 nm TSMC produktionsteknologi.

Med RV790 har AMD/ATI  formået at lave en GPU med hele 959 millioner transistorer og hele 800 Stream Processor Units.

Frekvensmæssigt ligger GPU-clockfrekvensen på HD4890 på 850 MHz, mens GDDR5-rammene kører ved 975 MHz. Dette er næsten det samme som HD4870, som HD4890 direkte skal afløse. Men der er dog visse optimeringer (se nærmere under specifikationer). AMD/ATI's HD4890 GPU er endvidere mindre varmeudviklende end tidligere modeller, hvilket gør at kortene kan designes ret støjsvage. Og MSI R4890 har da også en yderst effektiv referencekøleløsning monteret, samt en effektiv BIOS der er tunet til ekstrem ydelse, da kortet kommer overclocket fra fabrikanten af. R4890 kører nemlig med GPU'en sat til 880 MHz (mod standard 850) og RAM'ene sat til 999 MHz (mod standard 975). Og hvordan det spænder af kan I læse under Test og Overclocking.

 
(billedet er af en AMD silicium "wafer" til chipproduktion)

Grundet strømforbruget kræver HD4890 to 6-pins PCI-E strømkabler, og ikke kun et 6-pins som det ses på eksempelvis HD4770-baserede kort.

RV790 benytter et memory interface med en båndbredde på 256-bit. Større GPU'er som HD4870/HD4890, benytter 256-bit på memory interfacet. Til sammenligning kan nævnes NVIDIA's nyeste GTX-275 benytter 448-bit båndbredde og GTX-285 512-bit båndbredde. Man ser hér helt tydeligt effekten af, at AMD/ATI benytter de meget hurtigere GDDR5 RAM på HD4770 og HD4890 - og ikke GDDR3 RAM som NVIDIA. RAM-typen benyttet har voldsom effekt på ydelse på grafikkort, hvilket afspejles i hvad ydelse man får ud af GDDR5 RAM der benytter 256-bit og 128-bit busbåndbredde kontra GDDR3 RAM der benytter 512-bit busbåndbredde. Faktisk så har GDDR5 ram dobbelt så meget ydelse, som GDDR3 RAM per pin forbindelse. RV790 understøtter dog ikke PhysX, som NVIDIA har implementeret i deres GPU'er, hvilket afspejles i bl.a. 3DMark Vantage benchmarken.

Her får I lige AMD/ATI's korte liste over hvad RV790 GPU'en er i stand til:

ATI Radeon HD 4890 Series – Key Features

• TeraScale Graphics Engine - The TeraScale graphics engine in the ATI Radeon™ HD 4890 features over one teraFLOPS, nearly one billion transistors and 800 stream processors so you can enjoy the high resolutions and fast frame rates previously only available with dual-card systems⁴.
• Advanced Memory - GDDR5 provides twice the data per pin of GDDR3 memory at the same clock speeds.
• Enhanced Anti-Aliasing & Anisotropic Filtering - High performance anisotropic filtering and 24x custom filter anti-aliasing (CFAA) smooth jagged edges and create true-to-life graphics, for everything from grass to facial features.
• DirectX® 10.1 - Play today while preparing for tomorrow with state-of-the-art DirectX 10.1 graphics capabilities.
• ATI CrossFireX™ Technology - ATI CrossFireX™ technology with up to quad GPU support offers superior scalability so your system is ready to level up when you are³.
• PCI Express 2.0 - Support for PCI Express 2.0 will prepare you for bandwidth-hungry games and 3D applications.
• Power to Spare - This GPU has the brute processing power needed for physics, artificial intelligence, stream computing and ray tracing calculations.
• Unified Video Decoder 2 (UVD 2) - UVD 2 frees up your CPU for other tasks so you get The Ultimate Visual Experience™ for even the most processing-intensive content, including VC-1, H.264 and now MPEG-2. Also, take full advantage of Blu-ray functionality with dual-stream, picture in picture (PIP) capabilities^1,5.
• Accelerated Video Transcoding (AVT) - With ATI Stream technology, owners of ATI Radeon™ HD 4800 series graphics cards can help accelerate the conversion of standard and HD video into multiple formats for use on differing consumer electronics devices. The ATI Video Converter, designed to enable GPU transcoding of HD video streams, is currently available.
• Upscale Beyond 1080p - Watch the hottest Blu-ray movies or other HD content at full 1080p display resolution and beyond⁶.
• Enhanced DVD Upscaling - Watch standard DVD movies in near high-definition quality with DVD upscaling. The GPU uses post processing algorithms to enhance standard and low resolution videos and movies on your HD display.
• Dynamic Contrast - Dynamic Contrast automatically adjusts the contrast and brightness during scenes to consistently deliver a crisp, vibrant picture.
• HDMI - Enjoy the latest audio technologies using HDMI with 7.1 digital surround sound support. Also, xvYCC support allows the user to enjoy a wider range of color when connected to a capable HDTV.
• Dynamic Power Management - ATI Radeon HD 4890 GPUs deliver high performance when needed and conserve power when the demand on the graphics processor is low.
• Energy Efficient Manufacturing Process - Third generation 55nm chip uses the industry’s most energy efficient manufacturing process.