Author: Ben Sun · 10-13-2008
ATI has been releasing new video cards like there was no tomorrow recently. With the recent announcement of their moving away from owning their own Fabs and to a design powerhouse with some interest in a Fab company. AMD has decided to focus on building chipsets; CPUs and graphics cards at their Fabs have been sprung off into a new company Foundry Corporation which they own 44% of.
The high end of the graphics market has been dominated by the HD 4870 X2 cards which have two HD 4870 chips. The 512MB version of the HD 4870 has also been a success with performance that either matched or beat the GeForce GTX 260 in most cases and came close to the GeForce GTX 280 in some situations especially where computational power was important. ATI is launching the 1GB version of the HD 4870 today which is the same card as the HD 4870 with 1GB of memory.
The Radeon HD 4870 1GB is based upon ATI’s RV770XT chip that was announced earlier this year in the form of the HD 4870 512MB card. The chip is built at TSMC’s 55 nanometer process, allowing and is the second generation 55 nanometer chip. ATI’s first generation 55 nanometer chip was the HD 3xxx series and the second one is more efficient in terms of power usage to performance ratio. The HD 4870 is capable of doing 1.2 TeraFLOPS of computing power, compared to the 1 TeraFLOP on the HD 4850 and the 933 GigaFLOPS on the GeForce GTX 280.
ATI and S3 are the two companies that are supporting DirectX 10.1 on the market today. S3 is a minor player in the computer graphics card market with small market share compared to NVIDIA and ATI. DirectX 10.1 includes improvements to the Shaders and anti-aliasing of multiple render targets. The next major inflection point in graphics is DirectX 11 which is due sometime in the next two years. As games use features like Tessellation in DirectX 11, it should be interesting to see if developers use.
Graphics card memory has changed over the years going from SDRAM to DDR memory, to DDR2 memory to DDR3 memory. ATI used DDR4 memory in the last generation video cards based upon the HD 2900 but there isn’t much DDR4 memory in use today. GDDR3 memory on the other hand has been prevalent on graphics cards from both ATI and NVIDIA camps. GDDR5 memory has the effective ability to double the memory bandwidth of that offered by GDDR3 memory on the same clock speed. With a clock speed of 900MHz and a 256-bit memory bus bandwidth this means the HD 4870 has a effective memory bandwidth of 115.2GB/second.
The ATI card has the ability to work together with other HD4870 cards to improve performance. Their version of multiple graphics card solutions is called Crossfire. Depending on the motherboard being used and the number of expansion slots on that are on that motherboard. Some of the ATI chipset motherboards on the AMD side of things have four PCI Express x16 Generation 2.0 graphics card slots allowing up to four 4870 graphics cards to be installed at one time giving massive increases in performance over a single card.
ATI is really pushing the Universal Video Decoder 2 on their HD 4xxx series. They have had the distinction of having a video decoder the Theater series of chips on many older video cards. This allowed them to do hardware DVD decoding in a time when most video cards did software DVD decoding. The UVD2 has the ability to play two simultaneous HD content streams ala picture in a picture capability. This is useful for people that want to watch the DVD commentary at the same time as the actual movie on a Blu-Ray disc for example.
source : www.motherboards.org
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