Most high-end graphics cards today operate on GDDR3 or 4 memory, with ATI's X1950 series on 4 and Nvidia's 8800 series running on 3.
Moving to GDDR5 will mean lower voltages, smaller chips and higher frequencies, combined with increased bandwidth. The standard is currently defined at JEDEC, and is scheduled to be rolled out in a decent capacity next year.
Qimonda said that it had partnered with Advantest to get the kit sorted, and the company expects to be testing RAM to destruction (we presume) in the near future. You can check out the full text of the firm's thrilling statement here.