The world's fastest single-GPU graphics card is now available in stores, albeit in limited quantities. Newegg has most of its Radeon HD 7970 cards are listed for $550 with the slightly overclocked XFX Black Edition is pegged at $600.

We reviewed the Radeon 7970 last month and concluded while it comes at a substantial premium, the model offers excellent performance and fits snugly into AMD's top tier line-up.

Although it's pricey, the HD 7970 strikes somewhat of a balance in AMD's premium lineup when you compare it to the HD 6990. The dual-GPU card was 17% faster while costing 27% more and consuming 30% more power.

The HD 7970 might not deliver the same bang for your buck proposition as AMD's previous generation flagship cards, but it has secured the performance crown for the time being. Based on the dozen games that we tested, the HD 7970 was 17% faster than the GeForce GTX 580 at 2560x1600 and just 14% slower than the GTX 590.

The Radeon HD 7970 is the first graphics card to sport AMD's Tahiti-based chip, a graphics core stuffed with 4.3 billion transistors using a 28nm process. It boasts a 384-bit memory bus capable of pushing 264GB of data per second, 2,048 stream processors, a mere 3-watt power draw while idling and can be automatically overclocked by 33 percent through AMD's Powertune software for those times you need a little boost.

Currently, Asus, Diamond, HIS, XFX, Powercolor, Sapphire and Visiontek have all thrown their hats into the arena with mostly similar offerings, one exception being the XFX Black Edition. Also, on Monday, a handful of custom gaming rig companies such as Maingear started allowing systems to be configured with the new cards.

Also, AMD announced the availability of a refreshed mobile graphics lineup, the Radeon HD 7000M series. The new chips will be based on new package designs allowing GDDR5 support, Vari-Bright, PowerPlay and dynamic switchable graphics for additional power savings. The press release states that HP and Lenovo will have laptops featuring these chips and one such laptop that springs to mind is the HP Envy Spectre.

With the Radeon HD 7970 now available, the 7950 is anticipated to be released next month. Like its upscale brother, it will also be based on Tahiti architecture but should prove to be a more popular mainstream option due to its expected affordability.