AMD's release of Ryzen processors is difficult to call smooth and problem-free. A lot of nerves for the first owners of systems based on these CPUs were spoiled both by the numerous problems of the memory controller, and the error in implementing the FMA3 instructions. Fortunately, AMD gradually solves all problems of this kind. In particular, in the latest update of the AGESA 1 libraries. 6 the compatibility with high-frequency modules DDR4 SDRAM. At the same time, as it turns out now, AMD has fixed yet another CPU error, which so far has not attracted the attention of the general public - the so-called "VME-bug".

The existence of the problem "VME-bug" became known on May 12. The bottom line was that Ryzen has an incorrect implementation of the INT instruction (generating a software interrupt) in the virtual 8086 (VME) mode, which is usually used to run old 8086 programs in a modern operating system environment. This problem is relevant and can be fixed in relatively old 32-bit versions of OC, for example, in Windows XP or Windows Server 2003 when executing 16-bit code in real time.

For current 64-bit operating systems VME-bug does not matter, but it still can manifest itself when running virtual machines with old OS.

But in this case, the problem can be circumvented by simply disabling the VME mode.

Nevertheless, despite the apparent insignificance of the described problem, AMD spent some resources on its solution. New libraries AGESA 1. 6 contain the code that corrects this error. After updating the motherboard BIOS to a version with a new version of AGESA, the VME-bug should not be more. Recall that another error Ryzen processors, regarding the execution of FMA-instructions, was eliminated in AGESA 1.