AMD's upcoming DirectX 11 Radeon series of graphics cards are expected to appear in October, according to uncomfirmed sources.

Digitimes.com reports that two DirectX 11 Radeon graphics cards (Radeon HD 5850 and Radeon HD 5870) will be released in October.

Although there are not any technical details available yet, the new cards will boast a power-efficient 40nm manufacturing technology (TSMC) and support for the next-generation DirectX 11 API.

Xbitlabs.com reports that the upcoming lineup includes the following cards: Hemlock, Cypress, Juniper, Redwood, Cedar.

Hemlock will come as a dual-chip solution, based on the RV870 chip, while Cypress will boast a single-GPU architecture based on the same graphics chip. Juniper will be targeted at the performance market and will ultimately replace the company's Radeon HD 4850 and HD 4870.

AMD has demonstrated the advantages of the DirectX 11 GPUs at the CEDEC 2009 conference held today in Japan. The company showcased the advantages of the DirectX 11 SDK keeping the specifications of the graphics card they used on the demo system secret. The demostration showed a 25% performance boost when the "Compute Shader 5.0" was enabled, as well as signifiantly better rendering using real-time tesselation teqniques. DirectX 11 features such as tessellation is expected to bring higher quality, superior performing games.

Nvidia is also expected to support the DirectX 11 with the new GT300 GPU, which should appear in products in December.