ATI's R520 was expected in May or early June but new rumours state that the company has delayed the R50 till autumn to concentrate on the development of its Multi VPU technology to counter NVIDIA's SLI.
Once this architecture is launched, ATI will follow with R520 announcement. We suggest that ATI will use a similar strategy it used with the R300, Radeon 9700 introduction when it announced cards in late July/August to have them in shops in September. This is what we expect to see this time again.
The Inquirer says that the R520 is already taped out and that this is just a marketing decision from ATI. More details at The Inquirer