AMD grabs fastest mobile GPU crown from Nvidia

AMD has scored another point over its graphics rival Nvidia with what it claims is the world's fastest single-GPU mobile graphics processor, the Radeon HD 6990M.

While the red team is unlikely to hold the crown for long in the fast-moving world of discrete graphics, the company's latest chip is certainly impressive enough. Based on the TeraScale 2 unified processor architecture and the Barts GPU core, the Radeon HD 6990M - a mobile equivalent to the company's high-end Radeon HD 6990 PCI Express graphics card design - features 1,120 stream processing units, 56 texture units, 128 Z/stencil ROP units, and 32 colour ROP units.

Connected to the system over a PCI Express 2.1 x16 bus and featuring a GDDR5 memory interface with up to 2GB of dedicated graphics RAM, that spells impressive performance. Running at an engine clock speed of 715MHz and a memory clock speed of 900MHz - offering 3.6Gb/s data rate and up to 115.2GB/s overall bandwidth - the GPU promises single-precision compute power of 1.6 teraflops.

By comparison, Nvidia's closest equivalent product - the GeForce GTX 580M, launched late last month - offers just shy of one teraflop of single-precision compute performance. With increasing numbers of developers looking to GPU offload to accelerate everything from video playback and encoding to web page rendering, that's a figure which could prove a major win for AMD.

To help take advantage of the impressive compute performance available with the Radeon HD 6990, AMD has included DirectCompute 11 support along with OpenCL 1.1, although sadly software support for the latter isn't due until 'later in 2011'.

The full DirectX 11 stack is also supported, including Shader Model 5, a programmable hardware tessellation unit, accelerated muti-threading, order-independent transparency, and HDR tetxure compression. The Khronos Group's OpenGL 4.1 is also supported.

Impressively for a mobile graphics chip, a full implementation of AMD's Eyefinity technology is included with support for up to six completely independently simultaneous displays. Each display can be added to a group and combined into a single large display, which could make laptops featuring the new Radeon chip popular with gamers.

For those who need the very best performance - and who don't mind having a battery that lasts a few minutes at best - CrossFireX is supported, allowing two Radeon HD 6990 chips to be combined into a single dual-GPU beast. While that might seem like overkill on such a powerful GPU, AMD has already got customers looking to implement the technology.

"Our customers can expect record breaking gaming with unmatched realism and blistering speeds in all Eurocom systems powered by AMD Radeon HD 6990M," crowed the company's president Mark Bialic in a launch statement, "in both single and AMD CrossFireX configurations."

Eurocom won't be alone in offering well-heeled gamers a dual-GPU system, either. "By offering two AMD Radeon HD 6990M graphics processors in our flagship M18x laptop, Alienware and AMD have come together to provide gamers the ultimate mobile experience," claimed Alienware's vice president Arthur Lewis. "At its core, the Alienware brand is about pushing the limits and finding new extremes in gaming performance."

Nvidia will surely be sore that it was only able to retain the title of 'world's fastest mobile GPU' for less than a month, but the company is likely not beaten yet.

With AMD on top - for now - the green camp will be keeping its engineers busy, working out how to squeeze some extra performance from its Fermi architecture.