Rambus promises fivefold speeding of graphics memory

By Steve Malone

Posted on 8 Jul 2005 at 10:46

Memory developer Rambus has announced a new version of its XDR memory interface that, it says, will improve graphics memory speeds by up to five times.

Rambus says that the newly announced XDR2 memory interface uses a micro-threaded DRAM core and other circuit enhancements to set the bar for data rates at a hefty 8GHz. Rambus says that makes it five times faster than today's best-in-class GDDR graphics solutions. By comparison, the current XDR1 specification, slated to appear in Sony's next generation PlayStation 3, runs at 4.8GHz.

The XDR2 interface is aimed squarely at the generation after next graphics market. As the demand for hyper-realistic graphics in games intensifies, more and more data in the form of polygons is processed through the graphics subsystem. The technique goes beyond video processing and Rambus says that the system can also be applied to high speed network routing and switching applications.

Laura Stark, vice president of the Platform Solutions Group at Rambus said 'XDR2 is our latest iteration of the XDR DRAM architecture and will help 3D games and graphics-intensive applications realise the high performance potential that users demand'.

Microthreading is a technique that allows multiple requests for data at the same time and addresses the problem of a growing gap between the clock speeds of bus interfaces and those of the core system. The amount of data that a controller must fetch to maintain optimum efficiency for each clock cycle has to rise in proportion. By allowing parallel data access across the bus, the graphics system can make better use of the available data rates.

Rambus has implemented several systems to manage the increased speeds of version two. XDR2 supports Adaptive Timing that adjusts the speed of XDR FlexPhase timing circuits to compensate for voltage and temperature variations in real time. It also features Transmit Equalization that minimises the effects of reflections and attenuation and DRSL Signalling.

Rambus says that the XDR2 memory interface is open to licence now and expects products based on the technology to ship by 2007.