AMD has confirmed it’s issuing an update to fix any possible Ryzen system crashes caused by the set of FMA3 instructions.
According to AMD, it has identified why FMA3 code is causing hangs on PCs powered by its new Ryzen processors. The company didn’t go in detail regarding the root cause of the problem, but it did say that BIOS changes will be distributed to board makers to resolve the issue.
“We are aware of select instances where FMA code can result in a system hang,” AMD said in a statement. “We have identified the root cause.”
AMD released three Ryzen-branded desktop processors earlier this month, that slot into the brand-new AM4 motherboards. The trio of processors, which include the Ryzen 7 1800X, the Ryzen 7 1700X, and the Ryzen 7 1700, offer a killer multithreading performance; however they were found to causing a hard system lock under specific demanding FMA3 workloads.
The problem was first spotted in an open-source CPU benchmark Flops (v2) by Alexander “Mystical” Yee. This simple benchmark has been tailored to provide separate binaries for each major x64 architecture, such as Bulldozer, Haswell, Skylake, and others.
Since the GitHub repository doesn’t have a binary version for AMD Zen, the Haswell-specific binary is used for testing Ryzen, as it adds support for the FMA3 instruction-set, which is also supported by AMD’s new processors.
However, it was found that machines using Ryzen processors crash on running the Haswell-specific binary, at “Single-Precision – 128-bit FMA3 – Fused Multiply Add.” What makes this bug more critical is the fact that a simple application with basic user privileges has the ability to cause Ryzen system crashes.
Even more, the FMA3 code could be executed through virtual machines, posing a security threat to AMD’s upcoming Zen-based Naples server processors.
Luckily, AMD has identified the root cause in time. The company is in the process of issuing the patch so keep an eye on your motherboard vendor’s website for an update. There is no mention of when the update will arrive, but it could be assumed to happen before the release of Ryzen 5 on April 11, so this launch is even more powerful than that of its elder sibling.