CPU-Z changes benchmarking algorithm for accuracy with Ryzen


— 2:00 PM on May 3, 2017

We don't use it here at TR, but the CPU-Z benchmark has served me well in my personal life as a figurative hand-to-the-forehead for poorly-performing systems. Starting with the latest CPU-Z release, version 1.79, benchmark results will be quite different from those gathered using previous versions. The change was prompted due to an issue with one of the benchmarking algorithms used by the software.

CPU-Z's developers say they saw unexpectedly-excellent results on AMD's Ryzen CPUs that ran counter to the new processors' real-world performance. After a thorough investigation, the team discovered that Ryzen CPUs were executing a certain sequence of integer instructions in a way that avoided an intentional delay, producing improperly-inflated benchmark numbers.

Ordinarily, that kind of automatic optimization would be welcome, but upon further investigation, the CPU-Z team failed to replicate that behavior with Ryzen CPUs in real-world situations. Furthermore, the team says that due to the extreme unlikelihood of that specific sequence of instructions showing up in non-benchmark software, it felt it would be best to revise CPU-Z to reflect real-world results more accurately.

The CPU-Z team says the new benchmark computes a two-dimensional noise function in a way that a game might use to generate procedural data. The benchmark is written in C++ and uses SSE2 instructions in the 64-bit version of the app. The 32-bit version soldiers on with the legacy x87 instructions. If you'd like to see how your chip measures up, you can grab CPU-Z 1.79 at the program's download page.

Tip: You can use the A/Z keys to walk threads.
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