ATI, graphics products group of Advanced Micro Devices, on Thursday unwrapped its new code-named RV790 graphics processing unit (GPU) that enables new performance heights for the ATI Radeon HD 4890 graphics card. While the new chip does not differ substantially from the RV770 launched in 2008, higher clock-speeds and additional overclocking potential allow new solution to offer radically higher framerate in video games.

“The ATI Radeon HD 4890 graphics card represents the AMD sweet spot strategy reloaded. With last year’s launch of the ATI Radeon HD 4850 and ATI Radeon HD 4870 products, we gave gamers great performance and an incredible value proposition. Today, we are doing it again. ATI Radeon HD 4890 graphics cards are incredible performers, priced to sell in all major markets worldwide,” said Rick Bergman, senior vice president and general manager of AMD’s graphics products group.

Just like its predecessor, ATI RV790 graphics processing unit features 800 stream processors, 40 texture units, 16 render back ends as well as 256-bit memory bus compatible with GDDR3, GDDR4 and GDDR5 memory types. The RV790 features 850MHz clock-speed, but add-in-card manufacturers may clock the new chips at speeds up to 1000MHz. ATI recommends its partners to clock 1GB of GDDR5 memory to 3900MHz.

While the RV790 chip resembles specifications of the RV770 and the chip is still made using 55nm general purpose process technology, the novelty is not hand-picked RV770 with high clock-speed potential, but a reworked graphics processor. In fact, the RV790 even has higher transistor count: it features 959 million transistors, 3 million higher compared to RV770.

“We have reconfigured the ASIC to support high clock-speeds than could be achieved on RV770. To achieve this, we have re-done the power distribution of the ASIC, re-timed it and also added larger de-coupling capacitors on the ASIC to clean up noise and increase signal integrity; this latter element is the primary cause of the increased transistor count. All of these changes, though, are in order to facilitate high clockspeeds and to allow us to run GDDR5 memories at higher rates,” explained David Baumann, a technical marketing manager at AMD.

The ATI Radeon HD 4890 graphics card is supported by a dozen add-in-board companies offering a variety of custom board and cooling solutions.  Partners include Asustek Computer, Club 3D, Diamond Multimedia, Force3D, GeCube, Gigabyte, HIS (Hightech Information Systems), Jetway, MSI, Palit Multimedia, PowerColor, Sapphire Technology, VisionTek and XFX. The boards are available immediately at manufacturer suggested retail price of $249, and priced at select e-tailers at as low as $229 after mail-in rebate.

Tags: ATI, AMD, Radeon, RV790, 55nm