The reason for the delay, industry sources have explained to us, is that the first B0 stepping of the processors that AMD shipped to motherboard manufacturers in March was chronically unstable. This forced AMD to rethink the design of the processor die, a process which takes time.
AMD has now allegedly fixed this instability with the new B1 stepping of the AM3+ processors, we’re told, although the fix comes at the cost of being able to overclock the chip. As a result, AMD is apparently hard at work on a second revision to the design, which should allow the processors to be overclocked.
These problems have pushed the back the processors' release date significantly, though, as motherboard manufacturers have only just started designing BIOSes for the processors as they haven’t had stable samples with which to work until now. However, one silver lining for AMD fans is that we were told that, apart from the known issues, the performance of the processors was good.
If the rumour is true, it would put motherboard manufacturers in the tricky situation of trying to sell AM3+ motherboards to the public without any AM3+ processors on the market for the next four months, however.