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AMD Confirms It's Issuing a Fix To Stop New Ryzen Processors From Crashing Desktops (digitaltrends.com)
AMD says the company has been able to figure out why FMA3 code is causing system hangs on PCs using a new Ryzen desktop processor. From a report: Although AMD didn't provide a detailed report on the problem's root cause, the company said that BIOS changes will be distributed to motherboard manufacturers to resolve the issue. Customers are encouraged to keep an eye on their motherboard vendor's website for an update. "We are aware of select instances where FMA code can result in a system hang," the company said. "We have identified the root cause." AMD released three Ryzen-branded desktop processors at the beginning of March that plug into motherboards based on AMD's new AM4 socket. The trio of processors include the Ryzen 7 1800X, the Ryzen 7 1700X, and the Ryzen 7 1700. However, all three reportedly cause a hard system lock when running certain FMA3 workloads. The problem was replicated across all three processors and a variety of motherboards.
K5 had a bug like that too. And let's not forget Athlon/Athlon XP era and AGP issues. The Piledriver Opterons required a patch to fix a bug in the hypervisor system which allowed for escape from a VM. AMD has had just as many horrible bugs as Intel, which can be summed up like this: Making flawless high-performance chips is difficult.
Look at an intel errata list some time. There are huge numbers of bugs in all CPU's in recent times. Bios patches trap the errant instructions and use a work around. Nothing really to see here. I've had several intel instabilities get resolved with a bios flash. It is yet another reminder to always wait a few months after major revisions for the dust to settle unless your goal is to actually be an early adopter for the hell of it.
FMA instructions are Fused Multiply Add instruction. Usually their are on SIMD registers and allow you to do "a += b *c". Modern cores can do that on a vector in a single cycle. Actually, they may be able to do more than one FMA on a vector register in a single cycle.
FMA are most commonly used to compute dot product, and are therefore very helpful in linear algebra. (And so they are useful in a ton of data mining algorithms.)
Here ya go I mean it doesn't say, "WONTFIX, LOL" verbatim, but there are 128 items in there labeled "No Fix", so they may as well say LOL after it.
But I can use FMA3 instructions on multiple Intel microarchitectures without it ever causing my system to freeze up. That's the kind of "quality" only AMD can provide.
Try TSX instruction in a Haswell or Broadwell.. Well if your bios haven't been updated by Intel to disabled the instructions completely.
Errata is unfortunately pretty common in CPUs these days. I hope this one is fixed without having to disable the entire extensions like Intel does.